YouTip

# Python3.x Python list() Function [ Python3 Built-in Functions](#) * * * `list()` is a built-in function in Python used to convert a sequence into a list. Lists are the most commonly used mutable sequence type in Python, allowing elements to be added, deleted, or modified at any time. The `list()` function can convert iterable objects such as tuples, strings, dictionaries, and sets into lists. **Word Definition**: `list` means "list" and is a mutable sequence type in Python. * * * ## Basic Syntax and Parameters ### Syntax Format list(iterable) ### Parameter Description * **Parameter iterable**: * Type: Iterable object (tuple, string, dictionary, set, etc.) * Description: The iterable object to be converted into a list. ### Function Description * **Return Value**: Returns a list. * **Special Value**: Returns an empty list `[]` if no arguments are provided. * * * ## Examples ### Example 1: Conversion from Other Sequences ## Example # Convert tuple to list t =(1,2,3,4,5) lst =list(t) print(lst)# Output: [1, 2, 3, 4, 5] # Convert string s ="hello" lst =list(s) print(lst)# Output: ['h', 'e', 'l', 'l', 'o'] # Convert dictionary (only takes keys) d ={"a": 1,"b": 2,"c": 3} lst =list(d) print(lst)# Output: ['a', 'b', 'c'] # Convert set s ={3,1,2} lst =list(s) print(lst)# Output: [1, 2, 3] (automatically sorted) # Empty list lst =list() print(lst)# Output: [] **Expected Output:** [1, 2, 3, 4, 5]['h', 'e', 'l', 'l', 'o']['a', 'b', 'c'][1, 2, 3][] **Code Analysis:** 1. Tuple converted to list, maintaining element order. 2. When converting a string, each character becomes an element of the list. 3. Dictionary conversion only includes keys. ### Example 2: Common List Operations ## Example # List can be modified after creation lst =list((1,2,3)) lst.append(4)# Add element lst.insert(0,0)# Insert element print(lst)# Output: [0, 1, 2, 3, 4] # List comprehension (a more concise way) lst =[x * 2 for x in range(5)] print(lst)# Output: [0, 2, 4, 6, 8] # Copy list original =[1,2,3] copy=list(original) print(copy)# Output: [1, 2, 3] **Expected Output:** [0, 1, 2, 3, 4][0, 2, 4, 6, 8][1, 2, 3] Lists are mutable; elements can be added, deleted, or modified at any time after creation. * * Python3 Built-in Functions](#) * * *