Dictionary

• Check key exists in dictionary dict: if key in dict:

• How to iterate: a good tutorial.

String

• Trimming:

s = s.strip()
s = s.lstrip()
s = s.rstrip()

• Replace:

s = s.replace('\t', ' ')

Debug

• str vs repr: https://www.geeksforgeeks.org/str-vs-repr-in-python/, https://stackoverflow.com/questions/1436703/difference-between-str-and-repr.