Concatenation
Python equivalent of Java StringBuffer? (Python 3, 2013)
Efficient String Concatenation in Python (Python 2, 2004)
Iterate
Iterating over a string
“Simply implement an iterator that defines a next() method, and implement an __iter__ method on a class to make it iterable.”
s = 'abcde' for c in s: print(c)
Reverse
Reverse string in Python (5 different ways)
s = s[::-1]