Python替换包含十六进制数字的子字符串

Question

如何在python中用新的十六进制值替换子字符串值（十六进制值0x20E00）？

 <d:var name="Length" value="0x20E00"/>

Answer 1

You could use a regular expression and re.sub() :

>>> import re
>>> s = '<d:var name="Length" value="0x20E00"/>'
>>> re.sub(r'0[xX][0-9a-fA-F]+', '0xdeadbeef', s)
'<d:var name="Length" value="0xdeadbeef"/>'

That said, if you're working with XML, you're much better off using an XML parser to manipulate it.

Answer 2

Here's a way using re.sub with look behind :

re.sub(r'(?<=value=\").*(?=\")', 'new hex value',s)
'<d:var name="Length" value="new hex value"/>'