Master Python’s Core Data Structures: Lists, Tuples, Dictionaries, and Sets

1 List (list)

Lists are created with square brackets [] and are ordered, mutable sequences.

1.1 List creation

<code>>> a = [1, 2.3, True, 'hello']</code>

1.2 Indexing

Python uses zero‑based indexing; the first element is 0 , the last can be accessed with -1 .

<code>>> a[0]
1
>>> a[3]
'hello'
>>> a[-1]
'hello'</code>

1.3 Modifying elements

Assign a new value to a specific index.

<code>>> a[1] = 'two'
>>> a
[1, 'two', True, 'hello']</code>

1.4 Adding elements

Use append , extend , or insert .

<code>>> a.append(10)
>>> a.extend([30, 40, 50])
>>> a.insert(2, False)
>>> a
[1, 'two', False, True, 'hello', 10, 30, 40, 50]</code>

1.5 Removing elements

Use pop or remove .

<code>>> a.pop(3)   # removes element at index 3
>>> a.remove(30)
>>> a
[1, 'two', False, True, 'hello', 10, 40, 50]</code>

2 Tuple (tuple)

Tuples are created with parentheses () and are immutable.

<code>>> b = (1, [3, 4], 'five')
>>> b[1][1]
4
>>> b[2] = 5   # raises TypeError because tuples cannot be modified</code>

3 Dictionary (dict)

Dictionaries are defined with curly braces {} using key:value pairs.

<code>>> c = {1:'Mon', 2:'Tues', 3:'Wed', 4:'Thu', 5:'Fri'}
>>> c[2]
'Tues'
>>> c[3] = 'W'
>>> c[6] = 'Sun'   # add new key
>>> c.pop(1)       # remove key 1
>>> c
{2:'Tues', 3:'W', 4:'Thu', 5:'Fri', 6:'Sun'}</code>

4 Set (set)

Sets are unordered collections of unique elements, created with curly braces {}.

<code>>> d = {1, 2, 3, 4}
>>> 1 in d
True
>>> d.pop()        # removes an arbitrary element
>>> d.remove(2)
>>> d1 = d | {7, 8} # union
>>> d & {1, 4}      # intersection</code>

5 Common functions

5.1 sum()

<code>>> e = [1, 2, 3]
>>> sum(e)
6
>>> f = (5, 6, 7)
>>> sum(f)
18
>>> j = {9, 10, 11}
>>> sum(j)
30</code>

5.2 len()

<code>>> len(e)
3
>>> len(f)
3
>>> len('hello')
5</code>

5.3 max() and min()

<code>>> max(e)
3
>>> min(f)
5</code>