How to Use the File readline() Method in Python
In this tutorial, you'll learn how to use the file readline() method in Python. The file readline() method reads and returns a single line from the file.
Python File readline() Syntax
The syntax of the file readline() method is as follows:
file.readline()
Remarks
- The readline() method reads a single line from the file.
- A newline character (\n) is left at the end of the string, and is only omitted on the last line of the file if the file doesn’t end in a newline.
- If you want to read all the lines of a file and convert them to a list, then use the readlines() method.
Examples
The following is the demo file named employee_list.txt file containing the following text:
1- ID: 001 | Name: Employee 001 | Department: Sales & Marketing
2- ID: 002 | Name: Employee 002 | Department: IT
3- ID: 003 | Name: Employee 003 | Department: Business Development
4- ID: 004 | Name: Employee 004 | Department: Finance & Accounting
5- ID: 005 | Name: Employee 005 | Department: IT
6- ID: 005 | Name: Employee 005 | Department: Finance & Accounting
Example 1: Read the First and Second Lines
The following code reads the 1st and 2nd lines of the file employee_list.txt:
employee_list_file = open("employee_list.txt", "r")
first_line = employee_list_file.readline()
second_line = employee_list_file.readline()
print (first_line)
print (second_line)
employee_list_file.close()
Output:
ID: 001 | Name: Employee 001 | Department: Sales & Marketing
ID: 002 | Name: Employee 002 | Department: IT
Example 2: Read the Top 4 Lines
The following code reads the top 4 lines of the file employee_list.txt, using the while loop and break statements:
employee_list_file = open("employee_list.txt", "r")
count = 0
while(True):
count += 1
print(employee_list_file.readline(), end="")
if count == 4:
break
employee_list_file.close()
Output:
1- ID: 001 | Name: Employee 001 | Department: Sales & Marketing
2- ID: 002 | Name: Employee 002 | Department: IT
3- ID: 003 | Name: Employee 003 | Department: Business Development
4- ID: 004 | Name: Employee 004 | Department: Finance & Accounting
Example 3: Read all Lines
The following sample code illustrates an example of how to loop through the file object using the for loop statement and read all lines from the file:
employee_list_file = open("employee_list.txt", "r")
for line in employee_list_file:
print (line, end='')
employee_list_file.close()
Output:
1- ID: 001 | Name: Employee 001 | Department: Sales & Marketing
2- ID: 002 | Name: Employee 002 | Department: IT
3- ID: 003 | Name: Employee 003 | Department: Business Development
4- ID: 004 | Name: Employee 004 | Department: Finance & Accounting
5- ID: 005 | Name: Employee 005 | Department: IT
6- ID: 006 | Name: Employee 006 | Department: Finance & Accounting
Example 4: Read and Convert a List of Items
The following code reads all the lines of a file named employee_list.txt and converts them to a list:
employee_list_file = open("employee_list.txt", "r")
lines = employee_list_file.readlines()
print(lines)
employee_list_file.close()
Output:
['1- ID: 001 | Name: Employee 001 | Department: Sales & Marketing\n', '2- ID: 002 | Name: Employee 002 | Department: IT\n', '3- ID: 003 | Name: Employee 003 | Department: Business Development\n', '4- ID: 004 | Name: Employee 004 | Department: Finance & Accounting\n', '5- ID: 005 | Name: Employee 005 | Department: IT\n', '6- ID: 006 | Name: Employee 006 | Department: Finance & Accounting']
In this tutorial, you've learned how to use the Python file readline() method. The file readline() method is a function to read and return a single line from a file.