Strings:

A string is a data type that represents text. Think of it as a sequence of characters (letters, numbers, symbols, or spaces) grouped together.

Note: The code presented here is for the programming language Python

Examples:

• "Hello, World!"
• "123"
• "user@email.com"

Creating Strings

Strings are created by wrapping text in quotes:

name = "Alice"
message = 'Hello there'

Most languages accept both single (') and double (") quotes.

Common String Operations

Concatenation (Joining Strings)

Combining two or more strings together:

first_name = "John"
last_name = "Doe"
full_name = first_name + " " + last_name  # Result: "John Doe"

Length

Finding how many characters are in a string:

message = "Hello"
length = len(message)  # Result: 5

Accessing Characters

Strings are indexed, meaning each character has a position (starting at 0):

word = "Python"
first_letter = word[0]   # Result: "P"
third_letter = word[2]   # Result: "t"

Case Conversion

Changing text to uppercase or lowercase:

text = "Hello World"
upper = text.upper()     # Result: "HELLO WORLD"
lower = text.lower()     # Result: "hello world"

For more string operations in Python, see.

Special Characters

Some characters need special notation:

• \n - New line (creates a line break)
• \t - Tab (adds indentation)
• \\ - Backslash (the actual \ character)
• \" - Quote mark inside a string

Example:

message = "Line 1\nLine 2"

String Immutability

Strings cannot be changed after creation. When you modify a string, you're actually creating a new one:

word = "Hello"
word = word + " World"  # Creates a NEW string "Hello World"

Common Mistakes

1. Mixing quote types incorrectly
   • Wrong: "Hello'
   • Right: "Hello" or 'Hello'
2. Forgetting quotes
   • Wrong: name = Hello
   • Right: name = "Hello"
3. Confusing strings with numbers
   • "5" + "3" gives "53" (text)
   • 5 + 3 gives 8 (math)

Key Takeaways

• Strings hold text data and are created with quotes
• You can join, slice, and transform strings
• Strings start counting at position 0
• Once created, strings don't change—operations create new strings
• String "5" is different from number 5