String Basics 10 XP Easy

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Welcome to Strings — one of the most common data types in coding interviews! Almost every company asks string questions. 📝

💡 Think of it like this: A string is just an array of characters. The string 'hello' is really ['h', 'e', 'l', 'l', 'o']. So all array techniques work on strings too!

s = 'hello'
print(s[0])       # 'h'  (access by index)
print(s[-1])      # 'o'  (last character)
print(len(s))     # 5    (length)
print(s[::-1])    # 'olleh' (reverse!)
print(s.upper())  # 'HELLO'
print(s.lower())  # 'hello'
print('ell' in s) # True (substring check)

Key string facts for interviews:

⚠️ Strings in Python are immutable — you can't change a character in-place
Converting to list and back: list(s) → modify → ''.join(list)
String comparison is O(n) — comparing character by character
Common techniques: two pointers, hash maps, sliding window

Essential string methods:

s.isalpha() — Is it all letters?
s.isdigit() — Is it all numbers?
s.isalnum() — Letters or numbers?
s.split() — Split into words
' '.join(words) — Join words with space
s.strip() — Remove whitespace from edges

📋 Instructions

Write a function `string_info(s)` that takes a string and prints: - The length - The first and last character - The string reversed - The string in uppercase - Number of vowels (a, e, i, o, u — case insensitive)

Use len(s) for length, s[0] and s[-1] for first/last, s[::-1] for reverse, s.upper() for uppercase. For vowels: sum(1 for c in s.lower() if c in 'aeiou').

🧪 Test Cases

Input

Run your code

Expected

Length: 7
First: C
Last: x
...

Expected output (6 lines)

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main.py

Hi! I'm Rex 👋

Output

Ready. Press ▶ Run or Ctrl+Enter.

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