python read from file write to other file

Question

file1 = open('/path/to/file1.txt', "r")
file2 = open('/path/to/file2.txt', "wa")
counter = 1

for line in file1:
    new_string = str(counter) + '\t' + line
    file2.write(new_string)
    counter += 1

I am trying to add a number to the beginning of every line in a file and append this line by line to a new file. There are 1189 lines of text in the original file and despite a number of attempts I only get 1168 lines in the new file. What's going on?

I added a print statement ( print str(counter) + " " + line), all the lines from the original file get printed out with the expected number beside them. The counter variable is 1190 after the loop runs.

EDIT: inserting file2.close() after the loop worked, all 1189 lines are in the second file now, but why?

Answer 1

您是否关闭正在写入的文件，即在循环后执行file2.close() ？

Answer 2

您的file1和file2指向您提供的代码示例中的相同文件。