summary of the information about different data structures in

Here's an organized summary of the information about different data structures in Python, along with methods to iterate over them as key-value pairs when applicable:

Feature by Data Structure

Feature	Dictionary	Set	List	String	Tuple
Definition	Stores key pairs	An unordered collection of unique elements	A sequential, mutable collection of any data type	A sequential, immutable collection of textual data	A sequential, immutable collection of any data type
Representation	{ 'a':[42], 'b':[23,6,1] }	{'^2', 'mc', 'equal', 'E'}	[ 'a','b', 3, 4 ]	"call me ishmael"	( 'commander','lambda')
How to create?	x = {}, x = dict()	x = set()	x = [], x = list()	x = "", x = str()	x = ('a','b',), x = tuple()
Is structure mutable and allow duplicate elements?	Immutable keys but mutable and duplicate values	Mutable but unique elements only	Mutable and allows duplicate elements	Immutable but allows duplicate elements	Immutable but allows duplicate elements
Is the structure iterable?	Yes (iterable over keys)	Yes	Yes	Yes	Yes

Methods and Iteration

Dictionary

• Methods: items(), keys(), values()
• Iteration:

  python
  d = { 'a': [42], 'b': [23, 6, 1] }
  for key, value in d.items():
      print(f"{key}: {value}")
  

Set

• Methods: No key-value methods, primarily add(), remove(), union(), etc.
• Iteration:

  python
  s = {'^2', 'mc', 'equal', 'E'}
  for element in s:
      print(element)
  

List

• Methods: Index-based methods, append(), extend(), insert(), remove(), etc.
• Iteration:

  python
  l = ['a', 'b', 3, 4]
  for index, value in enumerate(l):
      print(f"{index}: {value}")
  

String

• Methods: String-specific methods, split(), join(), find(), replace(), etc.
• Iteration:

  python
  s = "call me ishmael"
  for index, char in enumerate(s):
      print(f"{index}: {char}")
  

Tuple

• Methods: Tuple-specific methods, mainly count() and index()
• Iteration:

  python
  t = ('commander', 'lambda')
  for index, value in enumerate(t):
      print(f"{index}: {value}")
  

Summary

• Dictionary: Best for key-value paired data, mutable values, and iterable over keys.
• Set: Ideal for unique, unordered data, mutable, but no key-value pairs.
• List: Great for ordered, mutable collections with duplicates allowed.
• String: Immutable text data, iterated as characters.
• Tuple: Immutable ordered collections, can contain duplicates.