Strings

In programming, we don't call text "text" or "words" - we call it a String.

A String is simply a sequence of characters (letters, numbers, or symbols) strung together. In Python, you tell the computer that something is a String by wrapping it in quotation marks.

---

1. Three Ways to Create Strings

You can create strings in Python using single quotes, double quotes, or triple quotes for multi-line paragraphs:

# 1. Single quotes
first = 'Python'

# 2. Double quotes
second = "Python"

# 3. Triple quotes for multiple lines
paragraph = """This is
a multi-line
text paragraph."""

:::tip Apostrophes inside text Use double quotes when your text contains apostrophes so Python does not get confused by the single quote inside: "It's Python time!" :::

---

2. Combining Strings

You can join strings together using the + operator (called concatenation), or repeat them using *:

first_name = "Ravi"
last_name = "Kumar"

# Join two strings with a space in the middle
full_name = first_name + " " + last_name
print(full_name)  # Output: Ravi Kumar

# Repeat a string 5 times
stars = "*" * 5
print(stars)  # Output: *****

---

3. String Length

Use len() to count how many total characters (including spaces and punctuation) are inside a string:

message = "Hello"
print(len(message))  # Output: 5

empty_string = ""
print(len(empty_string))  # Output: 0

---

4. Converting Numbers to Strings

If you want to join text with numbers, you must first convert the number into a string using str():

age = 25
message = "I am " + str(age) + " years old"
print(message)  # Output: I am 25 years old

---

Tip: Adding strings together using + and str() can get messy if you have a lot of variables. In the next module (Input & Output), we will learn a much cleaner way to build sentences called f-strings!

---

5. Common Mistakes to Avoid

Mistake 1: Mismatched Quotes

Always match your opening and closing quotes.

# Wrong - opening with double quote and closing with single quote
text = "Hello'

# Right - matching quotes on both sides
text = "Hello"
text = 'Hello'

Mistake 2: Adding Strings and Numbers Directly

Python cannot add raw numbers and text together directly.

# Wrong - raises TypeError
result = "Age: " + 25

# Right - convert the number first using str()
result = "Age: " + str(25)

Mistake 3: Forgetting Quotes Around Words

Without quotes, Python thinks a word is a variable name.

# Wrong - Python searches for a variable named Kavya
name = Kavya

# Right - quotes tell Python this is text
name = "Kavya"