Python program to count the total number of lines in a file

Python program to count the total number of lines in a file :

In this tutorial, we will learn how to find the total number of lines in a file using python.

Actually, we will find out the total lines in a text file. With this tutorial, you will learn how to open a file and read it’s content in python. Python provides inbuilt methods to read, write, and delete a file. You can use these file methods out-of-the-box without importing any external module.

We are using one hard-coded file name in the program. But you can also get the file name from the user. The algorithm we are using in this program is as below :

Algorithm :

Open the file in read mode. For reading a file, we need to open it first. We are opening the file in read mode as we are only reading the content of the file.
Initialize one counter as 0. This counter will hold the total number of lines in the file.
Using a for loop, read the file line by line.
Increment the counter by 1 for each line. Keep the counter value increasing until the file reading is completed. The counter will hold the total number of lines at the end.
Finally, print out the counter, i.e. the total number of lines.

Python program :

#1
file_path = r"C:\Users\userName\Documents\image.txt"

#2
lines_count = 0

#3
with open(file_path,'r') as f:
  #4
  for l in f:
    #5
    lines_count = lines_count +1

#6
print("Total number of lines : ",lines_count)

The code is shared here on Github.

Explanation :

The commented numbers in the above program denote the step-numbers below:

Store the file path in the variable file_path. Change the file path to the path of the file you want to check.
Initialize one variable lines_count as 0. This variable will save the count of total lines in the above file.
Open the file in “read” mode or r. The open() method takes two arguments. The first argument is the file that we want to open and the second argument is the kind of permission that we want for opening the file. Here, we are opening the file in read mode, so ‘r’ string is passed as the second argument. If you want to write anything to the file, you will have to pass ‘w’ or if you want to append anything to the file, you will have to pass ‘a’ as the second argument.
Using one for loop, read the content of the file line by line. We have opened the file as ‘f’, i.e. the variable ‘f’ will hold the reference to the file we opened. The for loop is for reading all lines in that file variable, or in that file.
For each line, increment the value of lines_count by 1. As explained above, this counter is increased by one on each iteration of the loop. When the loop will exit, this variable will hold the total count of lines in the file.
Finally, print out the total number of lines i.e. lines_count.

Example Output :

Total number of lines :  7

Conclusion :

In this tutorial, we have learned how to count the total number of lines of a file in python. We have learned how to open a file and how to read its content. Try to run the example above and drop one comment if you have any queries.

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Python program to count the total number of lines in a file