在標籤和文本之間添加字符串

Question

我只是想在字符串的開始處添加（0或更多）選項卡之後的字符串。 即

a = '\t\t\tHere is the next part of string. More garbage.' 

（插入Added String here.） 到

b = '\t\t\t Added String here. Here is the next part of string. More garbage.' 

什麼是去做最簡單的/最簡單的方法是什麼？

Answer 1

簡單：

re.sub(r'^(\t*)', r'\1 Added String here. ', inputtext) 

的^插入符的字符串的開頭相匹配，\t製表符，其中有應該是零或更多（*）。圓括號捕獲替換字符串中使用的匹配標籤，其中\1將它們再次插入到需要添加的字符串前面。

演示：

>>> import re 
>>> a = '\t\t\tHere is the next part of string. More garbage.' 
>>> re.sub(r'^(\t*)', r'\1 Added String here. ', a) 
'\t\t\t Added String here. Here is the next part of string. More garbage.' 
>>> re.sub(r'^(\t*)', r'\1 Added String here. ', 'No leading tabs.') 
' Added String here. No leading tabs.'