如何将列表的每个元素写入文本文件的每一行？

Question

Using python, I've got the following list:

data = ['element0', 'element1', 'element2', 'element3']

And I want to write each element, into a new line of "myfile.txt", so I've been trying this:

for x in data:
    open("myfile.txt", "w").write(x + "\n")

Which gives me this (inside "myfile.txt"):

element3

I looks like each time it goes through the loop, it writes the element on top of the last.

Desired result (inside "myfile.txt"):

element0
element1
element2
element3

Answer 1

Just open the file object once :

with open("myfile.txt", "w") as fobj:
    for x in data:
        fobj.write(x + "\n")

I'm using the file as a context manager by passing it to the with statement; this ensures that the file is closed again after the block of code finishes.

Each time you open the file object with the 'w' (write) mode, the file is truncated , emptied out. You'd have to use the 'a' (append) mode to prevent the file being truncated.

However, opening the file just once is much more efficient.