[Python] Basic data types

There are several data structures in Python, the following are some key notes for reference

1. List
• Example: a=[1, 2, 3, 4, 5]
• Mutable (support modification of objects like a.append(6)
• Support stack operations like "pop", "append"
• looping (1 expression only) squares = [x**2 for x in range(10)]
• looping using traditional for
  for x in [1,2,3]:
      x = x**2
2. Tuple
• Example: tup = (1, 2, 3, 'wahaha') (Always enclosed with parentheses!)
• Immutable -> tup[0] = 100 -> Not allowed!!
• Can contain lists
  tup = (['a', 'b'], [1, 2])
• Tuple with single element should add trailing comma
  tupSingle = (a,)
  
3. Sets
• Example: a = set([1, 2, 3])
• No element duplicate
• Example: 1 in a , Output: True (Fast testing)
• Mutable
4. Dictionary
• Pretty similar to associative arrays in PHP
• {} -> Empty dict
• Mutable
• Example: cord = {'x' : 123.4, 'y' : 278.5}
• Get keys -> cord.keys() -> return list ['x', 'y']
• Fast Testing -> 'in'