Python：逐行解析和打印文本文件

Question

I have the following question. How can I print an output file line by line. A simple example that i can think is the following. Any idea?

import codecs
output=codecs.open('output.txt','w', encoding='UTF-8')
for i in range(5):
   output.writelines(str(i)+'\n')
output.close()

I import codecs because maybe the input can be something else and not just the value i .

I take the following result:

01234

instead of:

0
1
2
3
4

Answer 1

Your code does output newlines. Check that your editor recognizes \\n newlines. However, it does so by accident. writelines expects a sequence of lines:

with open('output.txt','w', encoding='UTF-8') as output:
  output.writelines(str(i)+'\n' for i in range(5))

Answer 2

Try using write instead of writelines .

writelines(sequence_of_strings) -> None. Write the strings to the file.

Note that newlines are not added. The sequence can be any iterable object producing strings. This is equivalent to calling write() for each string.

On the other hand:

write(str) -> None. Write string str to file.

Note that due to buffering, flush() or close() may be needed before the file on disk reflects the data written.