Strings

In this section, you will learn about strings in Python. Strings are sequences of characters, and they are used to represent textual data. We will cover topics such as creating strings, accessing characters in a string, string concatenation, string methods, and string formatting.

Creating Strings

In Python, you can create strings by enclosing characters in single quotes (”) or double quotes (“”). Here are some examples:

string1 = 'Hello, world!'
string2 = "Python is awesome"
string3 = '''This is a multi-line
string'''

Accessing Characters in a String

You can access individual characters in a string using indexing. Python uses zero-based indexing, where the first character is at index 0. Here’s an example:

string = "Hello, world!"

print(string[0])  # Output: H
print(string[7])  # Output: w

String Concatenation

You can concatenate strings using the `+` operator. This allows you to combine multiple strings into a single string. Here’s an example:

string1 = "Hello"
string2 = "world!"

result = string1 + " " + string2

print(result)  # Output: Hello world!

String Methods

Python provides many built-in methods to manipulate strings. Here are a few commonly used string methods:

string = "Hello, world!"

print(string.upper())        # Output: HELLO, WORLD!
print(string.lower())        # Output: hello, world!
print(string.startswith("H"))  # Output: True
print(string.endswith("ld!"))  # Output: True
print(string.replace("o", "X"))  # Output: HellX, wXrld!

String Formatting

String formatting allows you to create dynamic strings by inserting values into placeholders within a string. Here are a few examples of string formatting:

name = "Alice"
age = 25

greeting = "My name is {} and I'm {} years old.".format(name, age)
greeting2 = f"My name is {name} and I'm {age} years old."

print(greeting)   # Output: My name is Alice and I'm 25 years old.
print(greeting2)  # Output: My name is Alice and I'm 25 years old.