Python Strings

What Is A String?

A string is text in Python. It can contain letters, numbers, spaces, and symbols. Strings are written inside quotes.

name = "Asha"
message = 'Welcome to Python'

Single quotes and double quotes both work. Choose one style and use it consistently.

String Length

Use len() to count the number of characters in a string.

word = "Python"
print(len(word))

Output:

6

Spaces count as characters too.

Indexing Strings

Each character has an index. Python starts counting at 0.

word = "Python"

print(word[0])
print(word[1])

Output:

P
y

Negative indexes count from the end.

print(word[-1])

This prints n, the last character.

Slicing Strings

Slicing extracts part of a string.

word = "Python"
print(word[0:3])

Output:

Pyt

The slice starts at index 0 and stops before index 3.

You can leave out one side:

print(word[:2])
print(word[2:])

Useful String Methods

String methods return new strings or useful results.

text = "  Python Practice  "

print(text.strip())
print(text.lower())
print(text.upper())

strip() removes extra spaces at the ends. lower() and upper() change letter case.

Other useful methods include:

• replace(old, new) to replace text
• split() to break text into a list
• startswith() to test the beginning of text

Strings Are Immutable

Strings cannot be changed in place. This will not work:

word = "cat"
word[0] = "b"

Instead, create a new string:

word = "cat"
word = "b" + word[1:]
print(word)

This prints bat.

Common Mistakes

A common mistake is using an index that does not exist.

word = "Python"
print(word[6])

The last valid index is 5, so this raises an IndexError.

Another mistake is expecting string methods to edit the original value automatically.

name = "asha"
name.upper()
print(name)

This still prints asha. Store the result if you need it:

name = name.upper()

Quick Summary

• Strings store text.
• Use quotes to create strings.
• Indexing starts at 0.
• Slices stop before the ending index.
• String methods such as strip() and lower() return useful results.
• Strings are immutable, so create a new string when changing text.

Practice Quiz

Now practice this topic with MCQs and explanations:

Start the Python Strings quiz