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Python File readline() Method with Example

Python File readline() Method: Here, we are going to learn about the readline() method, how to get the one line from the file in Python?
Submitted by IncludeHelp, on December 22, 2019

File readline() Method

readline() method is an inbuilt method in Python, it is used to get one line from the file, the method is called with this object (current file stream/IO object) and returns one line from the file, we can also specify the total number of bytes to read from the line.

Syntax:

    file_object.readline(bytes)

Parameter(s):

  • bytes – It is an optional parameter and it can be used to specify the total number of bytes to read from the file. It's default value is -1 that specifies the whole line.

Return value:

The return type of this method is <class 'str'>, it returns the string.

Example 1:

# Python File readline() Method with Example

# creating a file
myfile1 = open("hello1.txt", "w")

# writing content in the file
myfile1.write("Shivang, 21, Indore\n")
myfile1.write("Pankaj, 27, Mumbai\n")
myfile1.write("Rambha, 16, Heaven\n")

# closing the file
myfile1.close()

# reading the file (opening file in 'r' mode)
myfile1 = open("hello1.txt","r")

# reading and printing the file's content  
# line by line
print("file's content (using readline() method)...")
print("line1: ", myfile1.readline())
print("line2: ", myfile1.readline())
print("line3: ", myfile1.readline())

# reading and printing the file's content
# all at once using read() method

# seeking the file position at 0th position
myfile1.seek(0)
print("file's content (using read() method)...")
print(myfile1.read())

# closing the file
myfile1.close()

Output

file's content (using readline() method)...
line1:  Shivang, 21, Indore

line2:  Pankaj, 27, Mumbai

line3:  Rambha, 16, Heaven

file's content (using read() method)...
Shivang, 21, Indore
Pankaj, 27, Mumbai
Rambha, 16, Heaven

Example 2:

# Python File readline() Method with Example

# creating a file
myfile1 = open("hello1.txt", "w")

# writing content in the file
myfile1.write("Shivang, 21, Indore\n")
myfile1.write("Pankaj, 27, Mumbai\n")
myfile1.write("Rambha, 16, Heaven\n")

# closing the file
myfile1.close()

# reading the file (opening file in 'r' mode)
myfile1 = open("hello1.txt","r")

# reading and printing the file's content  
# line by line
print("file's content (using readline() method)...")
# reads whole line
print("line1: ", myfile1.readline(-1))
# reads 5 bytes
print("line2: ", myfile1.readline(5))
# reads next 10 bytes
print("line3: ", myfile1.readline(10))

# closing the file
myfile1.close()

Output

file's content (using readline() method)...
line1:  Shivang, 21, Indore

line2:  Panka
line3:  j, 27, Mum





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