How to Write Files in Python
Python like many other languages has built-in functions to write files, to write a file we need first to open a file.
Python like many other languages has built-in functions to write files, to write a file we need first to open a file.>>> with open("t1.txt") as file:
... file.write("Hello world")
...
Traceback (most recent call last):
File "<stdin>", line 2, in <module>
io.UnsupportedOperation: not writable
Oh! wait it threw an error! why? the open command by default opens a file in “read” mode, so any write attempt will drive to an exception. There are two ways to open a file for writing and we need to be super-careful about what to choose when:
- the write mode “w” this mode deletes any content of the file while opening the file, so use this mode when you are sure that you want to delete any previous content before writing.$ cat t1.txt
line1
line2
line3kpatronas@prometheus:~$ python
Python 3.8.10 (default, Mar 15 2022, 12:22:08)
[GCC 9.4.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> with open("t1.txt","w") as file:
... file.write("hello")
...
5
>>> exit()
kpatronas@prometheus:~$ cat t1.txt
hello - The append mode “a” this mode appends any new .write() content to the end of the file.$ cat t1.txt
line1
line2
line3
kpatronas@prometheus:~$ python
Python 3.8.10 (default, Mar 15 2022, 12:22:08)
[GCC 9.4.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> with open("t1.txt","a") as file:
... file.write("hello\n")
...
6
>>> exit()
kpatronas@prometheus:~$ cat t1.txt
line1
line2
line3
hello
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