how to count number of lines in a file python code example

Example 1: python how to count the lines in a file

# Basic syntax:
count = len(open('/path/to/the/file.ext').readlines())

Example 2: how to know how much lines a file has using python

filename = "test.txt"
count = 0
with open(filename, 'r') as f:
    for line in f:
        count += 1
print("Total number of lines is:", count)

Example 3: Write a Python program to count the number of lines in a text file.

def countlines(fname,mode='r+'):
	count=0
	with open(fname) as f:
		for _ in f:
			count += 1
	print('total number of lines in file : ',count)

countlines('file1.txt')

##########################

with open('file1.txt') as f:
	print(sum(1 for _ in f))

###########################
'''You can use len(f.readlines()),
 but this will create an additional list in memory,
  which won't even work on huge files that don't fit in memory.

'''