String Methods

String methods empower search, tokenization, validation, and manipulation of text.

Key Concepts & Detailed Explanation

Essential methods:

• .split(delim): Splits string by delimiter into a list of words.
• delim.join(list): Joins list elements into a single delimited string.
• .find(sub): Returns index of first occurrence (-1 if not found).
• .count(sub): Returns occurrence count of substring.
• .startswith(prefix) / .endswith(suffix): Returns boolean.
• .isalpha() / .isdigit() / .isalnum(): Checks character composition.

Code Examples & Output

Expected Output:

Best Practices & Common Pitfalls

Use 'in' operator for simple existence checks ('Python' in sentence); use .find() only when you need the index.

Practice Quiz

1. What does 'text.find("xyz")' return if "xyz" is not present in 'text'?

• A) None
• B) False
• C) -1
• D) ValueError

2. Which method checks if a string consists entirely of digits?

• A) isnumber()
• B) isnumeric() / isdigit()
• C) check_digit()
• D) has_digits()

Practice Challenge

Write a program that takes a comma-separated list of student names, strips whitespace from each, and joins them with ' & '.