Various functionality of data objects in Python.txt

Lists

Lists are ordered collections of items that can be of any data type. Lists are created using square brackets [] and items are separated by commas.


# Create a list
lst = [1, 2, 3, 'a', 'b', 'c']

# Access items in a list
lst[0]  # returns 1
lst[-1] # returns 'c'

# Modify an item in a list
lst[0] = 10

# Append an item to a list
lst.append('d')

# Insert an item at a specific index
lst.insert(0, 0)

# Remove an item from a list
lst.remove(2)

# Sort a list
lst.sort()

# Reverse a list
lst.reverse()

# Check if an item is in a list
5 in lst  # returns False
'b' in lst  # returns True

# Get the length of a list
len(lst)  # returns 6
Tuples

Tuples are similar to lists, but they are immutable, meaning that once they are created, their items cannot be modified. Tuples are created using parentheses () and items are separated by commas.


# Create a tuple
tup = (1, 2, 3, 'a', 'b', 'c')

# Access items in a tuple
tup[0]  # returns 1
tup[-1] # returns 'c'

# Check if an item is in a tuple
5 in tup  # returns False
'b' in tup  # returns True

# Get the length of a tuple
len(tup)  # returns 6
Dictionaries

Dictionaries are collections of key-value pairs. They are created using curly braces {} and keys are separated from values by a colon :.


# Create a dictionary
dct = {'a': 1, 'b': 2, 'c': 3}

# Access values in a dictionary
dct['a']  # returns 1

# Modify a value in a dictionary
dct['a'] = 10

# Add a new key-value pair to a dictionary
dct['d'] = 4

# Remove a key-value pair from a dictionary
del dct['b']

# Check if a key is in a dictionary
'e' in dct  # returns False
'c' in dct  # returns True

# Get the keys of a dictionary
dct.keys()  # returns ['a', 'c', 'd']

# Get the values of a dictionary
dct.values()  # returns [10, 3, 4]

# Get the length of a dictionary
len(dct)  # returns 3