在Python中包含3组的正则表达式模式

Question

I am trying to understand regex in Python. I'm trying to trying this pattern:

string = re.sub(r'(\".+?\")(: )', '\"here!\": ', string)

for this kind of string:

{ some text "data": { "first": "xyz" some text}

I expected this to replace "first": "xyz" but to my surprise the string which is replaced is: "data": { "first": "xyz" . Why is that? I have no idea why is it working in such way.

Answer 1

Your regular expression is matching the first portion of the input string surrounded by double quotes and followed by a colon, so it hits "data" before "first" .

I would go for a regular expression of:

'{\s*("\w+"):'

This will match the opening brace followed by some optional whitespace, then select the alphanumeric text in double quotes followed by a colon.

Also, you don't need to escape your double quotes as you are using a single quote as the delimiter for your regular expression.