Python – How to search for a string in text files?



Python – How to search for a string in text files?

In this article, we are going to see how to search for a particular string in a text file.

Consider below text File :

 

 

 

Example 1: we are going to search string line by line if the string found then we will print that string and line number.

Steps:

  • Open a file.
  • Set variables index and flag to zero.
  • Run a loop through the file line by line.
  • In that loop check condition using the ‘in’ operator for string present in line or not. If found flag to 0.
  • After loop again check condition for the flag is set or not. If set string found then print a string and line number otherwise simply print the message ‘String not found’.
  • Close a file.

Code:

string1 = 'coding'
 
# opening a text file
file1 = open("geeks.txt", "r")
 
# setting flag and index to 0
flag = 0
index = 0
 
# Loop through the file line by line
for line in file1:  
    index + = 1
     
    # checking string is present in line or not
    if string1 in line:
       
      flag = 1
      break
         
# checking condition for string found or not
if flag == 0
   print('String', string1 , 'Not Found'
else
   print('String', string1, 'Found In Line', index)
 
# closing text file    
file1.close() 

Output:

Example 2: We are just finding string is present in the file or not.

Step:

  • open a file.
  • Read a file and store it in a variable.
  • check condition using ‘in’ operator for string present in the file or not.
  • If the condition true then print the message ‘string is found’ otherwise print ‘string not found’.
  • Close a file.

Code:

string1 = 'portal'
 
# opening a text file
file1 = open("geeks.txt", "r")
 
# read file content
readfile = file1.read()
 
# checking condition for string found or not
if string1 in readfile: 
    print('String', string1, 'Found In File')
else
    print('String', string1 , 'Not Found'
 
# closing a file
file1.close() 

Output:

Last Updated on March 1, 2022 by admin

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