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Xcode vs Swift

Xcode and Swift are two different products developed by Apple for macOS, iOS, iPadOS, watchOS, and tvOS. While Xcode is an integrated development environment (IDE) for macOS containing a suite of software development tools to develop software for macOS, iOS, iPadOS, watchOS, and tvOS, Swift is a general-purpose, multi-paradigm, compiled programming language developed iOS, macOS, watchOS, tvOS, Linux, and z/OS. So it is clear that they can not be compared with each other. On the contrary, Swift is compatible with Xcode as Swift v 5.1, the default version of Swift is included in Xcode v 11. In this article, we will go through what Xcode and Swift are in general and cover their features strengths and weaknesses followed by how Swift is compatible with Xcode. XcodeIt was first released in 2003 as version 1 with the latest stable one being version 10.2.1 released on 17 April 2019. It can be downloaded from the Mac App Store and is free to use for macOS Mojave users. Registered developers may download the preview releases and previous versions of the suite using via the Apple Developer website.  Overview of the major featuresSupport: Programming languages such as C, C++, Objective-C, Objective-C++, Java, AppleScript, Python, Ruby, ResEdit (Rez), and Swift are supported by Xcode with source code along with support for a variety of programming models including Cocoa, Carbo, and Java. Not only that, there is additional support via third parties for GNU Pascal, Free Pascal, Ada, C#, Perl, and D Capability: Xcode can build fat binary files that include the code for various architectures in the Mach-O executable format. Known as universal binary files, these allow the application to run on both PowerPC and Intel-based (x86) platforms including both 32-bit and 64-bit codes Compiling and debugging: Xcode uses the iOS SDK to compile and debug applications for iOS that run on ARM architecture processors GUI tool: Xcode comprises of the GUI tool, Instruments that runs dynamic tracing framework on the top of DTrace, a dynamic tracing framework designed by Sun Microsystems and released as a part of OpenSolaris. Advantages and disadvantages of Xcode: Xcode is designed by Apple and will only work with Apple operating systems: macOS, iOS, iPadOS, watchOS, and tvOS. Since its release in 2003, Xcode has made significant improvements and the latest version, Xcode 10.2.1 has all the features that are needed to perform continuous integration. Let us have a look at the pros of using Xcode: Equipped with a well designed and easy to use UI creator Excellent for code completion Using Xcode, a developer can learn profiling and heap analysis in a natural way Xcode’s simulator lets you easily test your app while you build it in an environment that simulates your iPhone The app store has a wide range of audience who are willing to pay for apps. Now, the cons: Clunky and outdated Objective C makes it more frustrating if you are habituated to use a modern language No support for tabbed work environments makes it difficult to work with multiple windows Hardly any information can be found online to solve problems due to a previous Apple NDA on Xcode development It is a complicated process to export your app onto a device Will only work with Apple operating systems The App Store approval process can be annoyingly lengthy.SwiftSwift was launched at Apple's 2014 Worldwide Developers Conference as a general-purpose, multi-paradigm, compiled programming language for iOS, macOS, watchOS, tvOS, Linux, and z/OS Being a new entry these operating systems, Swift accelerates on the best parts of C and Objective C without being held back by its compatibility. It utilises safe patterns for programming, adding more features to it, thus making programming easier and more flexible. By developing their existing debugger, compiler and framework infrastructure, it took quite some time to create the base for Swift. Furthermore, Automatic Reference Counting was used to simplify the memory management part. The framework stack which was once built upon a solid framework of Cocoa and Foundation has undergone significant changes and is now completely regulated and refurbished. Developers who have worked with Objective-C do find Swift quite similar. Objective-C’s dynamic object model and its comprehensively named parameters provide a lot of control to Swift.  Developers can use Swift to have access to the existing Cocoa framework in addition to the mix and match interoperability with an objective C code. Swift uses this common rule to offer multiple new features in combination with object-oriented and procedural portions of the language. The idea is to create the best possible language for a wide range of uses, varying from desktop and mobile apps, systems programming, and scaling up to cloud services. The designing of Swift was done to make sure that developers find it easy to maintain and write correct programs. Coding done in Xcode is safe, fast and expressive. Swift offers a host of features that give developers the control needed to make the code easy to read and write. Furthermore, Apple made Swift to be easily understandable to help developers avoid making mistakes while coding and make the code look organised, along with the modules that give namespaces and eliminate headers. Since Swift uses some features present in other languages, one of them being named parameters written with clean syntax that makes the APIs much easier to maintain and read. Here are some of the additional features of Swift: Multiple return values and Tuples Generics Short and quick iterations over a collection or range Structs that support extensions, methods and protocols Functional programming patterns Advanced control flow Powerful error handling. These features are systematically designed to make them work together resulting in creating a powerful but fun-to-use language. Advantages and disadvantages of Swift: Pros of using the Swift Programming language: Easy to read and maintain: The Swift program codes are based on natural English as it has borrowed syntaxes from other programming languages. This makes the language more expressive Scalable: Users can add more features to Swift, making it a scalable programming language. In the future, Swift is what Apple is relying on and not Objective C Concise: Swift does not include long lines of code and that favours the developers who want a concise syntax, thus increasing the development and testing rate of the program Safety and improved performance: It is almost 40% better than the Objective-C when speed and performance are taken into consideration as it is easy to tackle the bugs which lead to safer programming Cross-device support: This language is capable of handling a wide range of Apple platforms such as iOS, iOS X, macOS, tvOS, and watchOS. Automatic Memory Management: This feature present in Swift prevents memory leaks and helps in optimizing the application’s performance that is done by using Automatic Reference Counting. Cons of Swift: Compatibility issues: The updated versions Swift is found to a bit unstable with the newer versions of Apple leading to a few issues. Switching to a newer version of Swift is the fix but that is costly Speed Issues: This is relevant to the earlier versions of the Swift programming language Less in number: The number of Swift developers is limited as Swift is a new programming language Delay in uploading apps: Developers will be facing delays over their apps written in Swift to be uploaded to the App Store only after iOS 8 and Xcode 6 are released. The estimated time for release is reported to be September-October, 2014. Conclusion So as we discussed both Xcode and Swift, it is clear that they cannot be compared to each other. In fact, they both complement each other to deliver impressive results without any headaches. Apple relies on both quite a lot and it is certain to have Swift and Xcode the perfect combination of a robust application and a user-friendly programming language.

Xcode vs Swift

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Xcode vs Swift

Xcode and Swift are two different products developed by Apple for macOS, iOS, iPadOS, watchOS, and tvOS. While Xcode is an integrated development environment (IDE) for macOS containing a suite of software development tools to develop software for macOS, iOS, iPadOS, watchOS, and tvOS, Swift is a general-purpose, multi-paradigm, compiled programming language developed iOS, macOS, watchOS, tvOS, Linux, and z/OS. So it is clear that they can not be compared with each other. On the contrary, Swift is compatible with Xcode as Swift v 5.1, the default version of Swift is included in Xcode v 11. 

In this article, we will go through what Xcode and Swift are in general and cover their features strengths and weaknesses followed by how Swift is compatible with Xcode. 

XcodeXcode

It was first released in 2003 as version 1 with the latest stable one being version 10.2.1 released on 17 April 2019. It can be downloaded from the Mac App Store and is free to use for macOS Mojave users. Registered developers may download the preview releases and previous versions of the suite using via the Apple Developer website.  

Overview of the major features

Overview of the major features

  • Support: Programming languages such as C, C++, Objective-C, Objective-C++, Java, AppleScript, Python, Ruby, ResEdit (Rez), and Swift are supported by Xcode with source code along with support for a variety of programming models including Cocoa, Carbo, and Java. Not only that, there is additional support via third parties for GNU Pascal, Free Pascal, Ada, C#, Perl, and D 
  • Capability: Xcode can build fat binary files that include the code for various architectures in the Mach-O executable format. Known as universal binary files, these allow the application to run on both PowerPC and Intel-based (x86) platforms including both 32-bit and 64-bit codes 
  • Compiling and debugging: Xcode uses the iOS SDK to compile and debug applications for iOS that run on ARM architecture processors 
  • GUI tool: Xcode comprises of the GUI tool, Instruments that runs dynamic tracing framework on the top of DTrace, a dynamic tracing framework designed by Sun Microsystems and released as a part of OpenSolaris. 

Advantages and disadvantages of Xcode: 

Advantages and disadvantages of Xcode

Xcode is designed by Apple and will only work with Apple operating systems: macOS, iOS, iPadOS, watchOS, and tvOS. Since its release in 2003, Xcode has made significant improvements and the latest version, Xcode 10.2.1 has all the features that are needed to perform continuous integration. 

Let us have a look at the pros of using Xcode: 

  • Equipped with a well designed and easy to use UI creator 
  • Excellent for code completion 
  • Using Xcode, a developer can learn profiling and heap analysis in a natural way 
  • Xcode’s simulator lets you easily test your app while you build it in an environment that simulates your iPhone 
  • The app store has a wide range of audience who are willing to pay for apps. 

Now, the cons: 

  • Clunky and outdated Objective C makes it more frustrating if you are habituated to use a modern language 
  • No support for tabbed work environments makes it difficult to work with multiple windows 
  • Hardly any information can be found online to solve problems due to a previous Apple NDA on Xcode development 
  • It is a complicated process to export your app onto a device 
  • Will only work with Apple operating systems 
  • The App Store approval process can be annoyingly lengthy.

SwiftSwift symbol

Swift was launched at Apple's 2014 Worldwide Developers Conference as a general-purpose, multi-paradigm, compiled programming language for iOS, macOS, watchOS, tvOS, Linux, and z/OS Being a new entry these operating systems, Swift accelerates on the best parts of C and Objective C without being held back by its compatibility. It utilises safe patterns for programming, adding more features to it, thus making programming easier and more flexible. By developing their existing debugger, compiler and framework infrastructure, it took quite some time to create the base for Swift. Furthermore, Automatic Reference Counting was used to simplify the memory management part. The framework stack which was once built upon a solid framework of Cocoa and Foundation has undergone significant changes and is now completely regulated and refurbished. 

Developers who have worked with Objective-C do find Swift quite similar. Objective-C’s dynamic object model and its comprehensively named parameters provide a lot of control to Swift.  

Developers can use Swift to have access to the existing Cocoa framework in addition to the mix and match interoperability with an objective C code. Swift uses this common rule to offer multiple new features in combination with object-oriented and procedural portions of the language. 

The idea is to create the best possible language for a wide range of uses, varying from desktop and mobile apps, systems programming, and scaling up to cloud services. The designing of Swift was done to make sure that developers find it easy to maintain and write correct programs. 

Coding done in Xcode is safe, fast and expressive. 

Swift offers a host of features that give developers the control needed to make the code easy to read and write. Furthermore, Apple made Swift to be easily understandable to help developers avoid making mistakes while coding and make the code look organised, along with the modules that give namespaces and eliminate headers. Since Swift uses some features present in other languages, one of them being named parameters written with clean syntax that makes the APIs much easier to maintain and read. Here are some of the additional features of Swift: 

Additional features of swift

  • Multiple return values and Tuples 
  • Generics 
  • Short and quick iterations over a collection or range 
  • Structs that support extensions, methods and protocols 
  • Functional programming patterns 
  • Advanced control flow 
  • Powerful error handling. 

These features are systematically designed to make them work together resulting in creating a powerful but fun-to-use language. 

Advantages and disadvantages of Swift: 

Advantages and disadvantages of Swift

Pros of using the Swift Programming language: 

  • Easy to read and maintain: The Swift program codes are based on natural English as it has borrowed syntaxes from other programming languages. This makes the language more expressive 
  • Scalable: Users can add more features to Swift, making it a scalable programming language. In the future, Swift is what Apple is relying on and not Objective C 
  • Concise: Swift does not include long lines of code and that favours the developers who want a concise syntax, thus increasing the development and testing rate of the program 
  • Safety and improved performance: It is almost 40% better than the Objective-C when speed and performance are taken into consideration as it is easy to tackle the bugs which lead to safer programming 
  • Cross-device support: This language is capable of handling a wide range of Apple platforms such as iOS, iOS X, macOS, tvOS, and watchOS. 
  • Automatic Memory Management: This feature present in Swift prevents memory leaks and helps in optimizing the application’s performance that is done by using Automatic Reference Counting. 

Cons of Swift: 

  • Compatibility issues: The updated versions Swift is found to a bit unstable with the newer versions of Apple leading to a few issues. Switching to a newer version of Swift is the fix but that is costly 
  • Speed Issues: This is relevant to the earlier versions of the Swift programming language 
  • Less in number: The number of Swift developers is limited as Swift is a new programming language 
  • Delay in uploading apps: Developers will be facing delays over their apps written in Swift to be uploaded to the App Store only after iOS 8 and Xcode 6 are released. The estimated time for release is reported to be September-October, 2014. 

Conclusion 

So as we discussed both Xcode and Swift, it is clear that they cannot be compared to each other. In fact, they both complement each other to deliver impressive results without any headaches. Apple relies on both quite a lot and it is certain to have Swift and Xcode the perfect combination of a robust application and a user-friendly programming language.

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Website : https://www.knowledgehut.com

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What are Python KeyError Exceptions and How to Handle Them

There are times when you have written your code but while you execute, it might not run. These types of situations occur when the input is inappropriate or you try to open a file with a wrong path or try to divide a number by zero. Due to some errors or incorrect command the output will not be displayed. This is because of errors and exceptions which are a part of the Python programming language. Learn about such concepts and gain further knowledge by joining Python Programming Course.What is Exception Handling?Python raises exceptions when it encounters errors during execution. A Python Exception is basically a construct that signals any important event, such as a run-time error.Exception Handling is the process of responding to executions during computations, which often interrupts the usual flow of executing a program. It can be performed both at the software level as part of the program and also at hardware level using built-in CPU mechanisms.Why is Exception Handling Important?Although exceptions might be irritating when they occur, they play an essential role in high level languages by acting as a friend to the user.An error at the time of execution might lead to two things— either your program will die or will display a blue screen of death. On the other hand, exceptions act as communication tools. It allows the program to answer the questions — what, why and how something goes wrong and then terminates the program in a delicate manner.In simple words, exception handling protects against uncontrollable program failures and increases the potency and efficiency of your code. If you want to master yourself in programming, the knowledge of exceptions and how to handle them is very crucial, especially in Python.What are the Errors and Exceptions in Python?Python doesn’t like errors and exceptions and displays its dissatisfaction by terminating the program abruptly.There are basically two types of errors in the Python language-Syntax Error.Errors occuring at run-time or Exceptions.Syntax ErrorsSyntax Errors, also known as parsing errors, occur when the parser identifies an incorrect statement. In simple words, syntax error occurs when the proper structure or syntax of the programming language is not followed.An example of a syntax error:>>> print( 1 / 0 )) File "", line 1 print( 1 / 0 ))   ^SyntaxError: invalid syntaxExceptionsExceptions occur during run-time. 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They are usually issued in situations where the user is alerted of some conditions. The condition does not raise an exception; rather it  terminates the program.What is a Python KeyError?Before getting into KeyError, you must know the meaning of dictionary and mapping in Python. Dictionary (dict) is an unordered collection of objects which deals with data type key. They are Python’s implementation of data structures and are also known as associative arrays. They comprise key-value pairs, in which each pair maps the key to its associated value.Dictionary is basically a data structure that maps one set of values into another and is the most common mapping in Python.Exception hierarchy of KeyError:->BaseException              ->Exception                         ->LookupError                                       ->KeyErrorA Python KeyError is raised when you try to access an invalid key in a dictionary. 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What are Python KeyError Exceptions and How to Han...

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How to Work With a PDF in Python

Whether it is an ebook, digitally signed agreements, password protected documents, or scanned documents such as passports, the most preferred file format is PDF or Portable Document Format. It was originally developed by Adobe and is a file format used to present and transfer documents easily and reliably. It uses the file extension .pdf. In fact, PDF being the most widely used digital media, is now considered as an open standard which is maintained by the International Standards Organization (ISO). Python has relatively easy syntax which makes it even easier for the ones who are in their initial stage of learning the language. The popular Python libraries are well suited and integrated which allows to easily extract documents from a PDF, rotate pages if required, split pdf to make separate documents, or add watermarks in them.Now an important question rises, why do we need Python to process PDFs? Well, processing a PDF falls under the category of text analytics. 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But since PyPDF4 is not fully backward compatible with the PyPDf2, it is suggested to use PyPDF2. You can also use a substitute package - pdfrw. Pdfrw was created by Patrick Maupin and allows you to perform all functions which PyPDF2 is capable of except a few such as encryption, decryption, and types of decompression.Some common libraries in PythonLet us look into some of the libraries Python offers to handle PDFs:PdfMiner It is a tool used to extract information from PDF documents. PDFMiner allows the user to analyze text data and obtain the definite location of a text. It provides information such as fonts and lines. We can also use it as a PDF transformer and a PDF parser.PyPDF2PyPDF2 is purely a Python library which allows users to split, merge, crop, encrypt, and transform PDFs. 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The types of data you can extract are:AuthorCreatorProducerSubjectTitleNumber of PagesTo understand it better, let us use an existing PDF in your system or you can go to Leanpub and download a book sample.The code for extracting the document information from the PDF—# get_doc_info.py from PyPDF2 import PdfFileReader def getinfo(path):     with open(path, 'rb') as f:         PDF = PdfFileReader(f)         information = PDF.getDocumentInfo()         numberofpages = PDF.getNumPages()     print(information)     author = information.author     creator = information.creator     producer =information .producer     subject = information.subject     title = information.title if __name__ == '__main__':     path = 'reportlab-sample.pdf'     getinfo(path)The output of the program above will look like—Here, we have firstly imported PdfFileReader from the PyPDF2 package. The class PdfFileReader is used to interact with PDF files like reading and extracting information using accessor methods. Then, we have created our own function getinfo with a PDF file as an argument and then called the getdocumentinfo(). This returned an instance of DocumentInformation. And finally we got extract information like the author, creator, subject or title, etc.getNumPages() is used to count the number of pages in the document. PdfMiner can be used when you want to extract text from a PDF file. It is potent and particularly designed for extracting text from PDF.We have learned to extract information from PDF. Now let’s learn how to rotate a PDF. Rotating pages in PDFA lot of times we receive PDFs which contain pages in landscape orientation instead of portrait. You may also find certain documents to be upside down, which happens while scanning a document or mailing. However, we can rotate the pages clockwise or counterclockwise according to our choice using Python with PyPDF2.The code for rotating the article is as follows—# rotate_pages.py from PyPDF2 import PdfFileReader, PdfFileWriter def rotate(pdf_path):     pdf_write = PdfFileWriter()     pdf_read = PdfFileReader(path)     # Rotate page 90 degrees to the right     page1 = pdf_read.getPage(0).rotateClockwise(90)     pdf_write.addPage(page1)     # Rotate page 90 degrees to the left     page2 = pdf_read.getPage(1).rotateCounterClockwise(90)     pdf_write.addPage(page2)     # Add a page in normal orientation     pdf_write.addPage(pdf_read.getPage(2))     with open('rotate_pages.pdf', 'wb') as fh:         pdf_write.write(fh) if __name__ == '__main__':     path = 'mldocument.pdf'     rotate(path)The output of the code will be as follows—Here firstly we imported the PdfFileReader and the PdfFileWriter so that we can write out a new PDF file. Then we declared a function rotate with a path to the PDF that is to be modified. Within the function, we created a read object pdf_read and write object pdf_write.Then, we used the getPage() to grab the pages. Two pages page1 and page2 are taken and rotated to 90 degrees clockwise and 90 degrees counterclockwise respectively using rotateClockwise() and rotateCounterClockwise().We used addPage() function after each rotation method calls. This adds the rotated page to the write object. The last page we add is page3 without any rotation.Lastly, we have used write() with a file-like parameter to write out the new PDF. The final PDF contains three pages, the first two will be in the landscape mode and rotated in reversed direction and the third page will be in normal orientation.Now we will learn to merge different PDFs into one.Merging PDFsIn many cases, we need to merge two PDFs into a single one. For example, suppose you are working on a project report and you need to print it and bind it into a book. It contains a cover page followed by the project report. So you have two different PDFs and you want to merge them into one PDF. You can simply use Python to do so. Let us see how can we merge PDFs into one.The code for merging two PDF documents using PyPDF in mentioned below:# pdf_merging.py from PyPDF2 import PdfFileReader, PdfFileWriter def pdfmerger(paths, output):     pdfwrite = PdfFileWriter()     for path in paths:         pdfread = PdfFileReader(path)         for page in range(pdfread.getNumPages()):             # Add each page to the writer object             pdfwrite.addPage(pdfread.getPage(page))     # Write out the merged PDF     with open(output, 'wb') as out:         pdfwrite.write(out) if __name__ == '__main__':     paths = ['document-1.pdf', 'document-2.pdf']     pdfmerger(paths, output='merged.pdf')Here we have created a function pdfmerger() which takes a number of inputs and a single output. Then we created a PdfFileReader() object for each PDF path and looped over the pages, added each page to the write object. Finally, using the write() function the object’s contents are written to the disk.PyPDF2 makes the process of merging simpler by creating the PdfFileMerger class.Code for merging two documents using PyPDF2—# pdf_merger2.py import glob from PyPDF2 import PdfFileMerger def merger(output_path, input_paths):     pdfmerge = PdfFileMerger()     file_handles = []     for path in input_paths:         pdfmerge.append(path)     with open(output_path, 'wb') as fileobj:         pdfmerge.write(fileobj) if __name__ == '__main__':     paths = glob.glob('d-1.pdf')     paths.sort()     merger('d-2.pdf', paths)The PyPDF2 makes it simpler in the way that we don’t need to loop the pages of each document ourselves.  Here, we created the object pdfmerge and looped through the PDF paths. The PyPDF2 automatically appends the whole document. Finally, we write it out.Let’s perform the opposite of merging now!Splitting PDFsThe PyPDF2 package has the ability to split up a single PDF into multiple PDFs. It allows us to split pages into different PDFs. Suppose we have a set of scanned documents in a single PDF and we need to separate the pages into different PDFs as per requirement, we can simply use Python to select pages we want to split and get the work done.Code for splitting a single PDF into multiple PDFs—# pdf_splitter.py import os from PyPDF2 import PdfFileReader, PdfFileWriter def splitpdf(path):     fname = os.path.splitext(os.path.basename(path))[0]     pdf = PdfFileReader(path)     for page in range(pdf.getNumPages()):         pdfwrite = PdfFileWriter()         pdfwrite.addPage(pdf.getPage(page))         outputfilename = '{}_page_{}.pdf'.format(             fname, page+1)         with open(outputfilename, 'wb') as out:             pdfwrite.write(out)         print('Created: {}'.format(outputfilename)) if __name__ == '__main__':     path = 'document-1.pdf'     splitpdf(path)Here we have imported the PdfFileReader and PdfFileWriter from PyPDF2. Then we created a function called splitpdf() which accepts the path of PDF we want to split. The first line of the function takes the name of the input file. Then we open the PDF and create a read object. Using the read object’s getNumPages(), we loop over all the pages.In the next step, we created an instance of PdfFileWriter inside the for loop. Then, we created a PDF write instance and added each page to it for each of the pages in the PDF input. We also created a unique filename using the original filename + the word ‘page’ + the page number + 1.Once we are done with running the script, we will have each of the pages of the input PDF split into multiple PDFs. Now let us learn how to add a watermark to a PDF and keep it secured.Adding Overlays/WatermarksAn image or superimposed text on selected pages in a PDF document is referred to as a Watermark. The Watermark adds security features and protects our rational property like images and PDFs. Watermarks are also called overlays.The PyPDF2 allows us to watermark documents. We just need to have a PDF which will consist of our watermark text, image or signature.Code for adding a watermark in a PDF—# watermarker.py from PyPDF2 import PdfFileWriter, PdfFileReader def watermark(inputpdf, outputpdf, watermarkpdf):     watermark = PdfFileReader(watermarkpdf)     watermarkpage = watermark.getPage(0)     pdf = PdfFileReader(inputpdf)     pdfwrite = PdfFileWriter()     for page in range(pdf.getNumPages()):         pdfpage = pdf.getPage(page)         pdfpage.mergePage(watermarkpage)         pdfwrite.addPage(pdfpage)     with open(outputpdf, 'wb') as fh:         pdfwrite.write(fh) if __name__ == '__main__':     watermark(inputpdf='document-1.pdf',               outputpdf='watermarked_w9.pdf',               watermarkpdf='watermark.pdf')The output of the code will look like— There are three arguments of the function watermark(): inputpdf: The path of the PDF that is to be watermarked. outputpdf: The path where the watermarked PDF will be saved. watermarkpdf: The PDF which contains the watermark.Firstly, we extract the PDF page which contains the watermark image or text and then open that PDF page where we want to give the desired watermark.Using the inputpdf, we create a read object and using the pdfwrite, we create a write object to write out the watermarked PDF and then iterate over the pages.Next, we call the page object’s mergePage and apply the watermark and add that to the write object pdfwrite.When the loop terminates, the watermarked PDF is written out to the disk and it’s done!Encrypting a PDFIn the PDF world, the PyPDF2 package allows an owner password which gives the user the advantage to work as an administrator. The package also provides the user password which allows us to open the document upon entering the password.The PyPDF2 basically doesn’t permit any allowances on any PDF file yet it allows the user to set the owner password and user password.Code to add a password and add encryption to a PDF—# pdf_encrypt.py from PyPDF2 import PdfFileWriter, PdfFileReader def encryption(inputpdf, outputpdf, password):     pdfwrite = PdfFileWriter()     pdfread = PdfFileReader(inputpdf)     for page in range(pdfread.getNumPages()):         pdfwrite.addPage(pdfread.getPage(page))     pdfwrite.encrypt(user_pwd=password, owner_pwd=None,                       use_128bit=True)     with open(outputpdf, 'wb') as fh:         pdfwrite.write(fh) if __name__ == '__main__':     encryption(inputpdf='document-1.pdf',                   outputpdf='document-1-encrypted.pdf',                   password='twofish')We declare a  function named encryption() with three arguments—the input PDF path, the output PDF path and the password that we want to keep. Then we create one read object pdfread and one write object pdfwrite. Now we loop over all the pages and add them to the write object since we need to encrypt the entire document.Finally, we call the encrypt() function which accepts three parameters—the user password, the owner password and the whether or not to use 128-bit encryption. The PDF  will be encrypted to 40-bit encryption if the argument use128bit is set to false. Also if the owner password is set to none, then it will be set to user password automatically.Reading the Table data from PDFSuppose you want to work with the Table data in Pdf, you can use tabula-py to read tables in a PDF. To install tabula-py, run:pip install tabula-pyCode to extract simple Text from pdf using PyPDF2:import tabula # readinf the PDF file that contain Table Data # you can find the pdf file with complete code in below # read_pdf will save the pdf table into Pandas Dataframe df = tabula.read_pdf("document.pdf") # in order to print first 5 lines of Table df.head()If you PDF file contains Multiple Tabledf = tabula.read_pdf("document.pdf",multiple_tables=True)If you want to extract Information from the specific part of any specific page of PDFtabula.read_pdf("document.pdf", area=(126,149,212,462), pages=1)If you want the output into JSON Formattabula.read_pdf("offense.pdf", output_format="json")Exporting PDF into ExcelSuppose you want to export a PDF into Excel, you can do so by writing the following code and convert the PDF Data into Excel or CSV.tabula.convert_into("document.pdf", "document_testing.xlsx", output_format="xlsx")Let us sum up what we have learned in the article:Extraction of data from a PDFRotate pages in a PDFMerge PDFs into one PDFSplit a PDF into many PDFsAdd watermarks or overlays in a PDFAdd password or encryption to a PDFReading table from PDFExporting PDF into Excel or CSVAs you have seen, PyPDF2 is one of the most useful tools available in Python. The features of PyPDF2 makes life easier whether you are working on a large project or even when you quickly want to make some changes to your PDF documents. Learn more about such libraries and frameworks as KnowledgeHut offers Python Certification Course for Programmers, Developers, Jr./Sr Software Engineers/Developers and anybody who wants to learn Python.
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How to Work With a PDF in Python

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Web Development Using PHP And MySQL

PHP (or PHP Hypertext Preprocessor) is a server-side scripting language that is used to create dynamic web pages that can interact with databases. It is a widely-used open source language that is specifically used for web application development and can be embedded within HTML. Why PHP? The distinguishing feature of PHP is that the scripting code is executed on the server, which generates HTML that is sent back to the client. The client receives the result of executing the script without knowing the underlying code. Developers can configure the web server to process all the HTML files (containing the PHP script). PHP course is easy to learn for any newcomer, but also offers advanced programming features. Using PHP with a database system PHP, as a scripting language, is popular among web developers because of its ability to interact with database systems including Oracle and MySQL. This article discusses the use of PHP scripting language with the MySQL database. Any website can require a variety of data or information to display and to retrieve them from the database. This can include display of a simple list to the running of the website based on data stored in the database. Listed below are some examples where PHP and MySQL can be used together: • Digital Ad banners, where the PHP script can be used to retrieve a digital banner from the database, which then selects a random banner from its table records and sends it back to the calling script. The PHP script can also maintain a count of banner views and clicks from the website. • Internet forums or digital boards, which use PHP and MySQL to store and retrieve user messages. • Website designing, where the design of an entire website can be changed using a couple of PHP scripts, instead of changing and uploading each web page. The PHP script can access the MySQL database to retrieve all information about the web page. Setting up the MySQL database The procedure of setting up the MySQL database varies according to the host. Every database would require a user name and password, in order to access the database. Database administration can be done using PHP scripts or using a program like PHPMyAdmin. The next step is to create the database tables for storing the website information. Creating a database table using PHPMyAdmin is also simple. Alternatively, one can create and configure the entire database using the following PHP script: CREATE TABLE tablename { Fields } Where the Fields are coded as fieldname type(length) extra_info Example: first varchar(15) NOT NULL The following command is used in the PHP script to connect to the MySQL database: mysql_connect(localhost,$username,$password); where: • localhost is the server address on which the web site is running, • $username is the user name for the database access • $password is the password for the database access Executing PHP commands After configuring and connecting to the MySQL database, you can start executing PHP commands on the server. Following are the 2 methods of executing a PHP command: • Entering the command in PHP using the following syntax: Mysql_query($query) This form of command can be used to repeat the command simply by changing the variable. • Defining the command as a variable. The result of the operation will be assigned to the variable. Data input and output Inserting data using PHP is identical to the procedure of data input using HTML pages. The advantage of using PHP is that the script does not need to be changed for each new piece of input data. Users can also input their own data on the web page. Following is an example of an HTML page with textboxes that can be used to enter data in a form: Alternatively, you can use variables to input information into the database. Example: $first=$_POST[‘first’]; $last=$_POST[‘last’]; $phone=$_POST[‘phone’]; $mobile=$_POST[‘mobile’]; $fax=$_POST[‘fax’]; $email=$_POST[’email’]; $web=$_POST[‘web’]; … $query = “INSERT INTO contacts VALUES (”,’$first’,’$last’,’$phone’,’$mobile’,’$fax’,’$email’,’$web’)”; mysql_query($query); This script is saved in the insert.php file, which can be called from the HTML form. Using this method, data entered in the web page form is stored in the defined variables, which are then passed to the PHP. To display (or output) the entered data using PHP, you can use the following MySQL command with the result assigned to the variable. $query=”SELECT * FROM contacts”; $result=mysql_query($query); PHP provides 2 submission methods, GET and POST to get the data submitted by the form into your PHP script. GET method displays the variables and the data in the page address, while they are invisible in the POST method. For example, a script can be created that will display different web pages depending on the clicked link. yourpage.php?user=david (to show David’s page) yourpage.php?user=tom (to show Tom’s page)
3957
Web Development Using PHP And MySQL

PHP (or PHP Hypertext Preprocessor) is a server-si... Read More