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Python program to reverse the content of a file and store it in another file

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Given a text file. The task is to reverse as well as stores the content from an input file to an output file. 
This reversing can be performed in two types.  

  • Full reversing: In this type of reversing all the content gets reversed. 
     
  • Word to word reversing: In this kind of reversing the last word comes first and the first word goes to the last position. 
     


Example 1: Full Reversing 
 

Input: Hello Geeks
       for geeks!
        

Output:!skeeg rof
        skeeG olleH
        


Example 2: Word to word reversing
 

Input: 
        Hello Geeks
        for geeks!

Output:
         geeks! for
         Geeks Hello


Example 1: Full Reversing 
Text file:
 

python-reverse-file-input


 

Python

# Open the file in write mode
f1 = open("output1.txt", "w")
 
# Open the input file and get
# the content into a variable data
with open("file.txt", "r") as myfile:
    data = myfile.read()
 
# For Full Reversing we will store the
# value of data into new variable data_1
# in a reverse order using [start: end: step],
# where step when passed -1 will reverse
# the string
data_1 = data[::-1]
 
# Now we will write the fully reverse
# data in the output1 file using
# following command
f1.write(data_1)
 
f1.close()

                    

Output:
 

python-reverse-file-output-1

Time complexity: O(n), where n is the length of the input file “file.txt”.

Auxiliary space: O(n), where n is the length of the input file “file.txt”.

Example 2: Reversing the order of lines. We will use the above text file as input.
 

Python3

# Open the file in write mode
f2 = open("output2.txt", "w")
 
 
# Open the input file again and get
# the content as list to a variable data
with open("file.txt", "r") as myfile:
    data = myfile.readlines()
 
# We will just reverse the
# array using following code
data_2 = data[::-1]
 
# Now we will write the fully reverse
# list in the output2 file using
# following command
f2.writelines(data_2)
 
f2.close()

                    

Output:
 

python-reverse-file-output-2


 



Last Updated : 20 Feb, 2023
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