I am curious about how Python implements typecasting from an integer to a string and its performance. I was trying to find the C function for str() in the source code's stringlib library but couldn't. For a concrete example, what happens when this is evaluated:
>> x = 123
>> y = str(x)
>> y
'123'
From what I've read in the stringlib source, I believe y is now a STRINGLIB_CHAR* object, which is CPython's extended char class (please correct me if wrong). However, what algorithm is used to convert from an integer 123 to a string "123"? Is the time complexity linear by size (in terms of digits n) or some other characteristic of the integer? Is it just repeatedly calling modulo on the integer, filling in the string buffer from the end to the front?