Python Programming Language Tutorial Part -1

Python Casting

In Python, casting refers to the process of converting a value from one data type to another. Python provides several built-in functions for casting, including int(), float(), str(), and bool().

Here are some examples of how to use casting in Python:

Casting to integer:

x = 3.14
y = int(x)
print(y) # Output: 3

Casting to floating-point number:

x = 5
y = float(x)
print(y) # Output: 5.0

Casting to string:

x = 10
y = str(x)
print(y) # Output: "10"

Casting to boolean:

x = ""
y = bool(x)
print(y) # Output: False

In addition to the built-in functions, Python also provides a way to create custom classes that define their own casting behavior. This is done by defining special methods, such as int() or float(), which allow instances of the class to be cast to the desired data type. However, this is an advanced topic and beyond the scope of this explanation.

Python String

In Python, a string is a data type used to represent text. Strings are defined using single quotes (‘…’) or double quotes (“…”), and can contain any combination of letters, numbers, and symbols. Here are some examples of how to define strings in Python:

my_string = "Hello, World!" # Using double quotes
another_string = 'This is a string' # Using single quotes

Strings can be manipulated using a variety of built-in functions and operators, such as concatenation (+), repetition (*), and slicing ([]). Here are some examples:

Concatenation:

first_name = "John"
last_name = "Doe"
full_name = first_name + " " + last_name
print(full_name) # Output: "John Doe"

Repetition:

my_string = "abc"
repeated_string = my_string * 3
print(repeated_string) # Output: "abcabcabc"

Slicing:

my_string = "Hello, World!"
substring = my_string[0:5] # Get the first 5 characters
print(substring) # Output: "Hello"

Python also provides many built-in methods for manipulating strings, such as upper(), lower(), strip(), split(), and join(). Here are some examples:

Upper and lower case:

my_string = "Hello, World!"
upper_case = my_string.upper()
lower_case = my_string.lower()
print(upper_case) # Output: "HELLO, WORLD!"
print(lower_case) # Output: "hello, world!"

Stripping whitespace:

my_string = " Hello, World! "
stripped_string = my_string.strip()
print(stripped_string) # Output: "Hello, World!"

Splitting and joining strings:

my_string = "Hello, World!"
split_string = my_string.split(", ")
joined_string = "-".join(split_string)
print(split_string) # Output: ["Hello", "World!"]
print(joined_string) # Output: "Hello-World!"

These are just a few examples of what you can do with strings in Python. Strings are an important and versatile data type in Python, and are used extensively in many programming applications.

Python Operator

In Python, an operator is a symbol or keyword used to perform operations on one or more operands. There are several types of operators in Python, including arithmetic operators, comparison operators, logical operators, identity operators, membership operators, and assignment operators.

Here are some examples of the different types of operators in Python:

Arithmetic operators:

x = 10
y = 3

print(x + y) # Output: 13
print(x - y) # Output: 7
print(x * y) # Output: 30
print(x / y) # Output: 3.3333...
print(x % y) # Output: 1
print(x ** y) # Output: 1000

Comparison operators:

x = 10
y = 3

print(x > y) # Output: True
print(x < y) # Output: False
print(x == y) # Output: False
print(x != y) # Output: True
print(x >= y) # Output: True
print(x <= y) # Output: False

Logical operators:

x = True
y = False

print(x and y) # Output: False
print(x or y) # Output: True
print(not x) # Output: False

Identity operators:

x = ["apple", "banana"]
y = ["apple", "banana"]
z = x

print(x is z) # Output: True
print(x is y) # Output: False
print(x == y) # Output: True

Membership operators:

x = "Hello, World!"
print("H" in x) # Output: True
print("h" in x) # Output: False
print("!" not in x) # Output: False

Assignment operators:

x = 10
x += 5 # Same as x = x + 5
print(x) # Output: 15

y = 5
y **= 3 # Same as y = y ** 3
print(y) # Output: 125

These are just a few examples of the different types of operators in Python. Operators are an essential part of the language and are used extensively in many programming applications.

Python Boolean

In Python, a boolean is a data type used to represent logical values, such as True or False. Booleans are primarily used in conditional statements and loops to control the flow of a program.

In Python, the True and False keywords are used to represent boolean values. Here are some examples:

x = True
y = False

print(x) # Output: True
print(y) # Output: False

Booleans can be combined using logical operators such as and, or, and not. Here are some examples:

x = True
y = False

print(x and y) # Output: False
print(x or y) # Output: True
print(not x) # Output: False

Booleans can also be created by comparing values using comparison operators such as ==, !=, <, >, <=, and >=. Here are some examples:

x = 5
y = 10

print(x == y) # Output: False
print(x != y) # Output: True
print(x < y) # Output: True
print(x > y) # Output: False
print(x <= y) # Output: True
print(x >= y) # Output: False

In Python, many functions and operators return boolean values, which can be used in conditional statements and loops. For example:

my_list = [1, 2, 3, 4, 5]

if 3 in my_list:
print("3 is in the list")
else:
print("3 is not in the list")