TypeError: 'str' object does not support item assignment

The following code is used to change the character at a certain position of the string , That's the problem

s = '312141'
s[0] = '0'

python String in with C++ It's a little different ,python The string of is a Immutable object (immutabel object), It means read-only and not write , Thread safety .C++ We can directly use the string of s[0]='0’ This syntax assigns a value to a character in a string , and python Can not be .
stay python in , You can first convert the string into a list , Then assign the value , Then turn it back . Reference resources stackoverflow One of the answers

s = '312141'
t = list(s)
t[0] = '0'
s = ''.join(t)