python - 在python中解析字符串

Question

所以我的问题是，我有一个如下所示的文件:

[SHIFT]this isrd[BACKSPACE][BACKSPACE] an example file[SHIFT]1

这当然会转化为

' This is an example file!'

我正在寻找一种将原始内容解析为最终内容的方法，这样 [BACKSPACE] 将删除最后一个字符(包括空格)，多个退格将删除多个字符。 [SHIFT] 对我来说并不那么重要。感谢所有的帮助!

Answer 1

这是一种方法，但感觉很老套。可能有更好的方法。

def process_backspaces(input, token='[BACKSPACE]'):
    """Delete character before an occurence of "token" in a string."""
    output = ''
    for item in (input+' ').split(token):
        output += item
        output = output[:-1]
    return output

def process_shifts(input, token='[SHIFT]'):
    """Replace characters after an occurence of "token" with their uppecase 
    equivalent. (Doesn't turn "1" into "!" or "2" into "@", however!)."""
    output = ''
    for item in (' '+input).split(token):
        output += item[0].upper() + item[1:]
    return output

test_string = '[SHIFT]this isrd[BACKSPACE][BACKSPACE] an example file[SHIFT]1'
print process_backspaces(process_shifts(test_string))