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))
##########################
with open('file1.txt') as f:
for lno , line in enumerate(f,1):
pass
print('total lines:',lno)
###########################
'''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.
'''