🟢 Level 1: Basic (Easy)
1️⃣ Create a string "Hello PHP" and print it.
2️⃣ Find the length of a string "Programming".
3️⃣ Convert "hello world" into:
- Uppercase
- Capitalized words
4️⃣ Reverse the string "OpenAI".
5️⃣ Check if the word "PHP" exists in "I love PHP programming".
🟡 Level 2: Intermediate
6️⃣ Concatenate two strings:
$first = "Web";
$second = "Development";
7️⃣ Extract "World" from "Hello World" using substr().
8️⃣ Remove extra spaces from:
" PHP is awesome "
9️⃣ Replace "Java" with "PHP" in:
"I love Java"
🔟 Count how many times "a" appears in "banana".
🟠 Level 3: Arrays + Strings
1️⃣1️⃣ Convert this string into an array:
"red,green,blue"
1️⃣2️⃣ Convert this array into a string:
["HTML", "CSS", "JS"]
1️⃣3️⃣ Split a sentence into words:
"PHP is easy to learn"
1️⃣4️⃣ Join words with -:
["2026", "03", "30"]
🔵 Level 4: Logic Based
1️⃣5️⃣ Check if a string is Palindrome
Example: "madam"
1️⃣6️⃣ Count total words in a string.
1️⃣7️⃣ Remove all vowels from a string.
1️⃣8️⃣ Find the longest word in a sentence.
1️⃣9️⃣ Convert a string into Title Case without using ucwords().
🔴 Level 5: Regex (Important)
2️⃣0️⃣ Check if a string contains only numbers.
2️⃣1️⃣ Validate an email address.
2️⃣2️⃣ Remove all digits from a string:
"abc123xyz456"
2️⃣3️⃣ Extract all numbers from a string.
2️⃣4️⃣ Check if a password contains:
- At least 1 number
- At least 1 uppercase letter
🟣 Level 6: Real-World Problems
2️⃣5️⃣ Create a username generator:
"Aditya Kumar Singh" → aditya_kumar
2️⃣6️⃣ Create a slug generator:
"Learn PHP in 2026!" → learn-php-in-2026
2️⃣7️⃣ Mask an email:
test@gmail.com → t***@gmail.com
2️⃣8️⃣ Count characters, words, vowels in a paragraph.
2️⃣9️⃣ Format currency:
1000000 → 10,00,000
🧠 Bonus Challenge (Advanced)
3️⃣0️⃣ Build a mini search system:
- Input: keyword
- Check if it exists in a paragraph
- Highlight matched word
🚀 Tip for Students
Practice in this order:
👉 Basic → Manipulation → explode/implode → Regex → Real projects
