Basic String Manipulation

String manipulation is a fundamental aspect of programming, allowing you to modify and work with text data effectively. Here are some common techniques:

Concatenation

Joining two or more strings together using the + operator. You will often use this when providing suitable output. Remember that you can only concatenate strings, so you might need to cast a number into a string before you attempt to use the + operator.

"Hello"+" "+"World"

Examples

stringA = "Hello"
stringB = "World"
print(stringA + stringB)  # Output: HelloWorld
print(stringA +" "+ stringB)  # Output: Hello World
print("Hello, your name is: " + name)  # Output: Hello, your name is: John

String Length

Getting the number of characters in a string.

Example:

subject = "ComputerScience"
print(len(subject))  # Output: 15

Substrings / Slicing

Examples:

subject = "ComputerScience"
print(subject[3:9])  # Output: puterS (substring from index 3 to 9)
print(subject[:4])  # Output: Comp (first 4 characters)
print(subject[-3:])  # Output: nce (last 3 characters)

Case Conversion

• Converting the whole string into uppercase or lower case

Examples

subject = "ComputerScience"
print(subject.upper())  # Output: COMPUTERSCIENCE
Lowercase: Convert all characters to lowercase.

subject = "ComputerScience"
print(subject.lower())  # Output: computerscience

ASCII Conversion

Definition: Converting characters to their ASCII values and vice versa.

Examples:

print(ord('A'))  # Output: 65 (ASCII value of 'A')
print(chr(97))  # Output: a (character for ASCII value 97)

String Tricks

Capitalise the first letter

• Extract First Letter: original_string[0] extracts the first character.
• Capitalize: .upper() converts it to uppercase.
• Concatenate: Combine the capitalized first letter with the rest of the string using +.

# Original string
original_string = "computerScience"

# Extract the first letter and capitalize it
first_letter = original_string[0].upper()

# Concatenate the capitalized first letter with the rest of the string
new_string = first_letter + original_string[1:]

print(new_string)  # Output: ComputerScience

Exam Reference Language

subject = "ComputerScience"
print(subject.length) # Output: 15

# Output: puterS (substring index 3 and 6 chars)
print(subject.substring(3,6)) 

print(subject.left(4)) # Output: Comp (first 4 characters)
print(subject.right(3)) # Output: nce (last 3 characters)

print(subject.upper) # Output: COMPUTERSCIENCE
print(subject.lower) # Output: computerscience

ASC(ꞌAꞌ) # returns 65 (numerical)
CHR(97) # returns ꞌaꞌ (char)