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Step-by-Step Guide to Reading Different Files in Python

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 In the world of data science, automation, and general programming, working with files is unavoidable. Whether you’re dealing with CSV reports, JSON APIs, Excel sheets, or text logs, Python provides rich and easy-to-use libraries for reading different file formats. In this guide, we’ll explore how to read different files in Python , with code examples and best practices. 1. Reading Text Files ( .txt ) Text files are the simplest form of files. Python’s built-in open() function handles them effortlessly. Example: # Open and read a text file with open ( "sample.txt" , "r" ) as file: content = file.read() print (content) Explanation: "r" mode means read . with open() automatically closes the file when done. Best Practice: Always use with to handle files to avoid memory leaks. 2. Reading CSV Files ( .csv ) CSV files are widely used for storing tabular data. Python has a built-in csv module and a powerful pandas library. Using cs...
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How to Decode TLV Quickly

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TLV format consists of three components: Tag, Length, and Value. In credit card and financial transactions, the TLV protocol utilizes this structure. Below, you will find tips for quickly decoding TLV data. 


TLV Format



According to IBM, the tag tells what type of data it is. The length field denotes the length of the value, and the value is the actual value.


Structure of TLV.


TLV comprises three field values.


  1. Tag
  2. Length
  3. Value


How to Decode TLV


The EMV labs developed tags that are part of the EMV protocol. Each tag has a unique meaning. The Tag and Length together take 1 to 4 bytes of memory.

1. The Best example for TLV.


Below is the method for decoding the EMV tag. The first part of the TLV format is TAG. The second part is LENGTH, and finally, the value.


Syntax of EMV tag:


[Tag][Value Length][Value] (ex. "9F4005F000F0A001")


where, 


Tag Name = 9F40


Value Length (in bytes) = 05 


Value (Hex representation of bytes. Example, "F0" – 1-byte) = F000F0A001


Finally, what is 9F40 tag? The EMV company assigns a value to it. Check out the complete list of EMV Tags and meanings.



2. How to read the TLV


Let me elaborate on the memory the EMV tag takes. The breakup of memory allocation is as follows.

 

Tag: 1 or 2 bytes.


Length: 05


Value length:


F0-00-F0-A0-01 ==> 5 Bytes


The F0 is the HEX value of length 1. So the total length of the value altogether is 5 bytes.


F0+00+F0+A0+01= Total 5 bytes



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