python - 在Python中使用正则表达式递归替换某些行

Question

我有一个文本文件，想要递归替换包含某些正则表达式模式的所有行，然后将结果保存到新的文本文件中。输入文本文件包含以下内容:

NAME1   184,743 184,439 14,305NAME2   84,343  64,437  36,335NAME3   154,543 174,439 38,385

I want to fill down all empty lines (including lines with only tabs and/or spaces) with the non-empty line above it. The final output should look like this:

NAME1   184,743 184,439 14,305NAME1   184,743 184,439 14,305NAME1   184,743 184,439 14,305NAME1   184,743 184,439 14,305NAME2   84,343  64,437  36,335NAME2   84,343  64,437  36,335NAME2   84,343  64,437  36,335NAME2   84,343  64,437  36,335NAME2   84,343  64,437  36,335NAME3   154,543 174,439 38,385NAME3   154,543 174,439 38,385NAME3   154,543 174,439 38,385NAME3   154,543 174,439 38,385

I tried this code but I can't figure how to make it work as I am new to Python. The regular expression works in Notepad++ but not in IDLE:

import re
fhand = open("/home/user1/Documents/inputtext.txt")
fout = open("/home/user1/Documents/outputtext.txt","w")

for line in fhand:
    re.sub("^(\S+.*)$(\n)^([\t ]+|)$","\1\2\1",line)
    fout.write(line)
fout.close()

Answer 1

您可以使用一个简单的循环来跟踪最后一行及其中的任何非空格:

last = '\n'
for line in fhand:
    # if the line isn't empty after stripping all whitespaces
    if line.strip():
        # save this line into the variable last for later blank lines to copy from
        last = line
    # otherwise it's a blank line
    else:
        # and we should copy from the non-blank line saved in the variable last
        line = last
    fout.write(line)
fout.close()