Python File Open

Open a File on the Server

Assume we have the following file, located in the same folder as Python:

demofile.txt

Hello! Welcome to demofile.txt
This file is for testing purposes.
Good Luck!

To open the file, use the built-in open() function.

The open() function returns a file object, which has a read() method for reading the content of the file:

Example

f = open("demofile.txt", "r")
print(f.read())

Show Python »
C:\Users\My Name>python demo_file_open.py
Hello! Welcome to demofile.txt           
This file is for testing purposes.       
Good Luck!                               
                                         
                                         

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Read Only Parts of the File

By default the read() method returns the whole text, but you can also specify how many characters you want to return:

Example

Return the 5 first characters of the file:

f = open("demofile.txt", "r")
print(f.read(5))

Show Python »
C:\Users\My Name>python demo_file_open2.py
Hello                                     
                                          
                                          

---

---

Read Lines

You can return one line by using the readline() method:

Example

Read one line of the file:

f = open("demofile.txt", "r")
print(f.readline())

Show Python »
C:\Users\My Name>python demo_file_readline.py
Hello! Welcome to demofile.txt               
                                             
                                             

By calling readline() two times, you can read the two first lines:

Example

Read two lines of the file:

f = open("demofile.txt", "r")
print(f.readline())
print(f.readline())

Show Python »
C:\Users\My Name>python demo_file_readline2.py
Hello! Welcome to demofile.txt                
This file is for testing purposes.            
                                              
                                              

By looping through the lines of the file, you can read the whole file, line by line:

Example

Loop through the file line by line:

f = open("demofile.txt", "r")
for x in f:
  print(x)

Show Python »
C:\Users\My Name>python demo_file_readline3.py
Hello! Welcome to demofile.txt                
This file is for testing purposes.            
Good Luck!                                    
                                              
                                              

---

Close Files

It is a good practice to always close the file when you are done with it.

Example

Close the file when you are finish with it:

f = open("demofile.txt", "r")
print(f.readline())
f.close()

Show Python »
C:\Users\My Name>python demo_file_close.py
Hello! Welcome to demofile.txt            
                                          
                                          

Note: You should always close your files, in some cases, due to buffering, changes made to a file may not show until you close the file.