Essential Built-in Functions in Python

2.10. Essential Built-in Functions in Python#

Python offers a series of “built-in” functions that are always available for use, without the need to import modules. They are fundamental for common operations and manipulating different data types.

2.10.1. print()#

The print() function is one of the most basic and frequently used in Python. It serves to display information on the console or to standard output.

  • Syntax: print(object(s), sep=' ', end='\n', file=sys.stdout, flush=False)

  • object(s): The item or items you want to print. It can be a string, a number, a list, etc.

  • sep (separator): An optional string to use as a separator between multiple objects. The default is a space.

  • end (terminator): An optional string that is added at the end of the output. The default is a newline character (\n).

  • Return: None (returns None).

print("Hello")

2.10.2. type()#

The type() function is used to return the type of an object. It is useful for debugging and understanding what kind of data you are working with.

  • Syntax: type(object)

  • object: The item whose type you want to determine.

  • Return: The type of the object.

print(type("Hello"))

2.10.3. len()#

The len() function returns the number of items (the “length”) of an object. It works for sequences like strings, lists, tuples, dictionaries, and sets.

  • Syntax: len(s)

  • s: The object whose item count you want to get.

  • Return: An integer representing the number of items.

print(len("Python"))

2.10.4. int()#

The int() function is used to convert a value to an integer type. It can convert floating-point numbers (by truncating the decimal part) or strings that represent whole numbers.

  • Syntax: int(x, base=10)

  • x: The value to be converted. It can be a number, or a string that represents a number.

  • base (optional): If x is a string, the numeric base (e.g., 2 for binary, 16 for hexadecimal). The default is 10.

  • Return: An integer value. If the conversion is not possible, it raises a ValueError.

print(int("123"))

2.10.5. str()#

The str() function is used to convert a value to its string representation.

  • Syntax: str(object)

  • object: The item to be converted to a string.

  • Return: The string representation of the object.

print(str(123))

2.10.6. float()#

The float() function is used to convert a value to a floating-point number type (decimal number). It can convert integers or strings that represent decimal numbers.

  • Syntax: float(x)

  • x: The value to be converted. It can be an integer, or a string that represents a number.

  • Return: A floating-point value. If the conversion is not possible, it raises a ValueError.

print(float("3.14"))

2.10.7. abs()#

The abs() function returns the absolute value of a number.

  • Syntax: abs(x)

  • x: A number (integer, float, or complex).

  • Return: The absolute value of x.

print(abs(-10))

2.10.8. max()#

The max() function returns the largest item in an iterable or the largest of two or more arguments.

  • Syntax: max(iterable, *[, key, default]) or max(arg1, arg2, *args[, key])

  • iterable: A collection of items (list, tuple, etc.).

  • arg1, arg2, *args: Individual arguments.

  • Return: The largest item.

print(max(1, 5, 10))

2.10.9. min()#

The min() function returns the smallest item in an iterable or the smallest of two or more arguments.

  • Syntax: min(iterable, *[, key, default]) or min(arg1, arg2, *args[, key])

  • iterable: A collection of items (list, tuple, etc.).

  • arg1, arg2, *args: Individual arguments.

  • Return: The smallest item.

print(min(1, 5, 10))

2.10.10. sum()#

The sum() function returns the sum of all items in an iterable.

  • Syntax: sum(iterable, /[, start])

  • iterable: A collection of numeric items (list, tuple, etc.).

  • start (optional): A number that is added to the sum of the items. The default is 0.

  • Return: The sum of the items, plus the start value.

print(sum([1, 2, 3]))

2.10.11. range()#

The range() function is used to generate an immutable sequence of numbers. It is commonly used to iterate a certain number of times in for loops.

  • Syntax:

    • range(stop): Generates numbers from 0 up to stop-1.

    • range(start, stop): Generates numbers from start up to stop-1.

    • range(start, stop, step): Generates numbers from start up to stop-1, incrementing (or decrementing) by step.

  • Parameters:

    • start (optional): The integer from where the sequence starts. The default is 0.

    • stop: The integer where the sequence stops (not included).

    • step (optional): The integer that determines the increment between each number in the sequence. The default is 1.

  • Return: A range object. To see the numbers, you can convert it to a list (e.g., list(range(5))).

# range(stop)
print(list(range(5)))
# Output: [0, 1, 2, 3, 4]

# range(start, stop)
print(list(range(2, 7)))
# Output: [2, 3, 4, 5, 6]

# range(start, stop, step)
print(list(range(1, 10, 2))) # Odd numbers
# Output: [1, 3, 5, 7, 9]

print(list(range(10, 0, -1))) # Countdown
# Output: [10, 9, 8, 7, 6, 5, 4, 3, 2, 1]
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