Built-In Functions In Python

In Python, built-in functions are functions that are provided by the Python interpreter and are always available for use without the need for importing any modules.

These functions serve different purposes and are commonly used in Python programming for performing different operations.

Here's an overview of some important built-in functions in Python:

Type Conversion:

int(), float(), str(), bool(): Convert values to integers, floating-point numbers, strings, or booleans.

Example:

# Converting string to int
strNumber = "88"
floatNumber = 3.14

intNumber = int(strNumber)
print(intNumber)  # Output: 88

# Converting float to int
intNumber = int(floatNumber)
print(intNumber)  # Output: 3

# Converting int to float
floatNumber = float(intNumber)
print(floatNumber)  # Output: 3.0

# Converting string to float
floatNumber = float(strNumber)
print(floatNumber)  # Output: 88.0

# Convert int to string
strNumber = str(intNumber)
print(strNumber)  # Output: "3"

# Convert float to string
strNumber = str(floatNumber)
print(strNumber)  # Output: "88.0"

list(), tuple(), set(), dict(): Convert iterable objects to lists, tuples, sets, or dictionaries.

Example:

# Converting string to list
strValue = "Good Morning"
listValue = list(strValue)
print(listValue)  
# Output: ['G', 'o', 'o', 'd', ' ', 'M', 'o', 'r', 'n', 'i', 'n', 'g']

# Converting  tuples list to dictionary
tuplesList = [("firstName", "Alice"), ("lastName", "Collin")]
dictValue = dict(tuplesList)
print(dictValue)  
# Output: {'firstName': 'Alice', 'lastName': 'Collin'}

# Converting list to tuple
listValue = [1, 2, 3, 4, 5, 6]
tupleValue = tuple(listValue)
print(tupleValue)  # Output: (1, 2, 3, 4, 5, 6)

# Converting list to set
listValue = [7, 7, 7, 0, 0, 0, 2, 3, 2]
setValue = set(listValue)
print(setValue)  # Output: {0, 2, 3, 7}

Input and Output:

print(): Print objects to the standard output.
input(): Read input from the user as a string.

Example: print() method

# Using print() to display message
print("Display message on screen inside print method")  
# Output: Display message on screen inside print method

Example: input() method

# Using input() to read user input
fullName = input("Enter your full name: ")
print("Hi,", fullName)  # Hi, <fullname depends on user input>

Mathematical Operations:

abs(): Return the absolute value of a number.
max(), min(): Return the maximum or minimum value among the given arguments.
sum(): Return the sum of elements in an iterable.

Example: abs() method

# Declare integer and assign value
intValue = -20

# Finding the absolute value
print(abs(intValue))  # Output: 20

Example: sum(), max() and min() methods

# Declare integer and assign value
marks = [50, 35, 45, 11, 60]

# Apply Built-in functions of python

#  Finding the maximum value
print(max(marks))  # Output: 60

#  Finding the minimum value
print(min(marks))  # Output: 11

# Calculating the sum of values
print(sum(marks))  # Output: 201

Iterable Operations:

len(): Return the length of an object (e.g., list, string, dictionary).
range(): Generate a sequence of numbers.
enumerate(): Return an iterator that yields tuples of index and value pairs.
zip(): Return an iterator that aggregates elements from multiple iterables.

Data Manipulation:

sorted(): Return a new sorted list from the elements of an iterable.
reversed(): Return an iterator that yields elements in reverse order.
filter(): Return an iterator that filters elements from an iterable based on a function.
map(): Return an iterator that applies a function to every item of an iterable.

Example: sorted() method

# Using lambda with sorted() to sort a list of tuples based on the second element

pairs = [(5, 'five'), (6, 'six'), (2, 'two')]
sortedPairs = sorted(pairs, key=lambda x: x[1])
print(sortedPairs)  # Output: [(5, 'five'), (6, 'six'), (2, 'two')]

Example: reversed() method

numbers = [1, 2, 3, 4, 5]
reverseNumber = reversed(numbers) # Output: return iterator object

print(list(reverseNumber)) # Output: [5, 4, 3, 2, 1]

Example: map() method

# Using lambda with map() to double each element of a list

numbers = [1, 2, 3, 4, 5]
squaredNumbers = list(map(lambda x: x * 2, numbers))
print(squaredNumbers)  # Output: [2, 4, 6, 8, 10]

Example: filter() method

# Using lambda with filter() to filter even numbers from a list

numbers = [2, 5, 7, 8, 10]
evenNumbers = list(filter(lambda x: x % 2 == 0, numbers))
print(evenNumbers)  # Output: [2, 8, 10]

Object Inspection:

type(): Return the type of an object.
id(): Return the identity (memory address) of an object.
isinstance(): Check if an object is an instance of a class.

Example:

# Declare string and assign value
strValue = "Welcome"

# Apply Built-in functions of python
print(type(strValue))  # Output: <class 'str'>
print(id(strValue))  # Output: 133694960265328
print(isinstance(strValue, str))  # Output: True

String Operations:

len(): Return the length of a string.
str.upper(), str.lower(): Convert a string to uppercase or lowercase.
str.strip(): Remove leading and trailing whitespace from a string.
str.split(), str.join(): Split a string into a list of substrings or join a list of strings into a single string.
str.replace(): accepts two arguments, the first argument source value that needs to be replaced and the second argument with whom it gets replaced.

Example:

strValue = "Welcome"
# get the length of a string
print(len(strValue))  # Output: 7

# String Methods
print(strValue.upper())  # Output: WELCOME
print(strValue.lower())  # Output: welcome
print(strValue.split())  # Output: ['Welcome']
print(strValue.replace("Welcome", "Hello"))  # Output: Hello


strValue = " Welcome "
print(len(strValue)) # Output: 9
print(strValue.strip()) # Output: Welcome

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