Python String Methods & Manipulation

String Concatenation

In Python, you can concatenate strings using the + operator or by using the str.join() method. Here are examples of both methods:

Method – Using the + operator

str1 = "Hello"
str2 = "World"
result = str1 + " " + str2
print(result)  # Output: Hello World

Method 2 – Using the str.join() method

str1 = "Hello"
str2 = "World"
result = " ".join([str1, str2])
print(result)  # Output: Hello World

Method 3 – Using f-strings (formatted string literals)

If you want to join multiples or mixed data types (like strings and integer) then f-strings are usually the easiest option. Otherwise you will need to use type casting with mystr = str(myint).

name = "Alice"
age = 25
height = 1.65
message = f"My name is {name}, I am {age} years old, and my height is {height} meters."

print(message)  # Output: My name is Alice, I am 25 years old, and my height is 1.65 meters.

String Slicing

In Python, string slicing allows you to extract a portion of a string by specifying a start and end index. The basic syntax for string slicing is string[start:end].

Example

text = "helloworld"

# Extracting a substring from index 3 to 7 (excluding index 7)
substring1 = text[3:7]
print(substring1)  # Output: lowo

# Extracting a substring from index -5 to the end
substring2 = text[-5:]
print(substring2)  # Output: world

# Extracting a substring from index 0 to the end with a step of 2
substring3 = text[0::2]
print(substring3)  # Output: hlool

# Reversing the string
reversed_text = text[::-1]
print(reversed_text)  # Output: dlrowolleh

Negative indexing

Negative indexing allows you to slice a string starting from the end of the string.

text = "helloworld"

# Extracting a substring starting from the second last character to the end
substring1 = text[-2:]
print(substring1)  # Output: ld

# Extracting a substring starting from the third last character to the fifth last character (excluding index -5)
substring2 = text[-3:-5]
print(substring2)  # Output: 

# Extracting a substring starting from the beginning to the fourth last character
substring3 = text[:-4]
print(substring3)  # Output: hellowo

# Reversing the string using negative step value
reversed_text = text[::-1]
print(reversed_text)  # Output: dlrowolleh

String Methods

Python provides several built-in string methods that you can use to perform various operations and manipulations on strings.

Programming Challenges

Challenge 1

Print the first three characters of a given word.

Challenge 2

Create a new word by concatenating the last three characters of the first word and the first three characters of the second word.

Challenge 3

Print the last character of a given word.

Challenge 4

Create a new word by reversing the order of characters in a given word.

Challenge 5

Extract the middle three characters from a given word.

Challenge 6

Create a new word by concatenating the first and last characters of a given word.

Challenge 7

Create a new word by concatenating the middle character and the last two characters of a given word.

Challenge 8

Create a new word by repeating a given word three times with a space between each repetition.

Challenge 9

Create a new word by repeating each character of a given word twice.

Challenge 10

Create a new word by concatenating the even-indexed characters and odd-indexed characters of a given word separately.