Python File Handling With Odinub

Hey Everyone in today’s post we will learn how to handle files in python with odinub.
In Python, there is no need for importing external library to read and write files.
Python provides an inbuilt function for creating, writing and reading files.
In this tutorial we will learn
•    How to create a Text File
•    How to Append Data to a File
•    How to Read a File 
•    How to Read a File line by line
•    File modes in a python

How to create a text file

With python you can create a text files by using a code that I have mentioned below
Step 1) Open a text file

f= open("odinub.txt","w+")

We declared the variable f to open a file named textfile.txt. Open takes 2 arguments, the file that we want to open and a string that represents the kinds of permission or operation we want to do on the file
Here we used "w" letter in our argument, which indicates write and the plus sign that means it will create a file if it does not exist in library
The available option beside "w" are "r" for read and "a" for append and plus sign means if it is not there then create it
Step 2) write data in file

for i in range(10):
     f.write("This is line %d\r\n" % (i+1))

We have a for loop that runs over a range of 10 numbers.
Using the write function to enter data into the file.
The output we want to iterate in the file is "this is line number", which we declare with write function and then percent d (displays integer)
So basically we are putting in the line number that we are writing, then putting it in a carriage return and a new line character
Step 3) Close the file when code is finish. 

 f.close()

This will close the instance of the file odinub.txt stored
Here is the result after code execution
You can see the output in "odinub.txt" file. The output of the code is that earlier file is appended with new data.
 

OUTPUT :

How to Append Data to a File

You can also append a new text to the already existing file or the new file.
Step 1) Open the file in write mode.

f=open("odinub.txt", "a+")

Once again if you could see a plus sign in the code, it indicates that it will create a new file if it does not exist. But in our case we already have the file, so we are not required to create a new file.
Step 2) Append data in to a file.

for i in range(2):
     f.write("Appended line %d\r\n" % (i+1))

This will write data into the file in append mode.

OUTPUT :

How to Read a File

Not only you can create .txt file from Python but you can also call .txt file in a "read mode"(r).

Step 1) Open the file in Read mode

f=open("odinub.txt", "r")

Step 2) We use the mode function in the code to check that the file is in open mode. If yes, we proceed ahead

if f.mode == 'r': 

Step 3) Use f.read to read file data and store it in variable content

contents =f.read() 

Step 4) print contents

 

Here is the output :

How to Read a File line by line

You can also read your .txt file line by line if your data is too big to read. This code will segregate your data in easy to ready mode.
When you run the code (contents=f.readlines()) for reading the file or document line by line, it will separate each line and present the file in a readable format. In our case the line is short and readable, the output will look similar to the read mode. But if there is a complex data file which is not readable, this piece of code could be useful.

OUTPUT :


File Modes in Python

Mode 
Description
'r' This is the default mode. It Opens file for reading.
'w' This Mode Opens file for writing.
If file does not exist, it creates a new file.If file exists it truncates the file.
'x' Creates a new file. If file already exists, the operation fails.
'a' Open file in append mode.
If file does not exist, it creates a new file.
't' This is the default mode. It opens in text mode.
'b' This opens in binary mode.
'+' This will open a file for reading and writing (updating)

 

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