readline() to read a line of text from a file in Python

readline(limit)

limit : optional upper limit of bytes returned.
Output is the line of data from the file.

fob=open('data.txt','r')
print(fob.readline()) # This is first line

Output is here ( used the data.txt file given at file read() ) Using limit

fob=open('data.txt','r')
print(fob.readline(5)) # This
fob.close()

Multiple lines of data

fob=open('data.txt','r')
print(fob.readline())
print(fob.readline())

Output

This is first line

This is second line

Handling End-of-Line Characters

The readline() method returns the line including the newline character:

fob = open('data.txt', 'r')
line = fob.readline()
print(repr(line))  # Output: 'This is first line\n'
fob.close()

When dealing with large files, readline() can be used to process them one line at a time without loading the entire file into memory:

with open('largefile.txt', 'r') as file:
    while line := file.readline():
        print(line.strip())