Write to an Existing File
To write to an existing file, you must add a parameter to the open() function:
"a" – Append – will append to the end of the file
"w" – Write – will overwrite any existing content
Example
Open the file “demofile2.txt” and append content to the file:
f = open(“demofile2.txt”, “a”)
f.write(“Now the file has more content!”)
f.close()
#open and read the file after the appending:
f = open(“demofile2.txt”, “r”)
print(f.read())
Output:
C:\Users\My Name>python demo_file_append.py
Hello! Welcome to demofile2.txt
This file is for testing purposes.
Good Luck!Now the file has more content!
Example
Open the file “demofile3.txt” and overwrite the content:
f = open(“demofile3.txt”, “w”)
f.write(“Woops! I have deleted the content!”)
f.close()
#open and read the file after the appending:
f = open(“demofile3.txt”, “r”)
print(f.read())
Output:
C:\Users\My Name>python demo_file_write.py
Woops! I have deleted the content!
Note: the “w” method will overwrite the entire file.
Create a New File
To create a new file in Python, use the open() method, with one of the following parameters:
"x" – Create – will create a file, returns an error if the file exist
"a" – Append – will create a file if the specified file does not exist
"w" – Write – will create a file if the specified file does not exist
Example
Create a file called “myfile.txt”:
f = open(“myfile.txt”, “x”)
Result: a new empty file is created!
Example
Create a new file if it does not exist:
f = open(“myfile.txt”, “w”)