Explain Joining and Splitting Strings in PHP.

Introduction

Strings often need to be combined or separated when preparing text for display, storage, or processing. This note shows how to join multiple strings into one and split a string into parts (examples use Python syntax). The same concepts apply in other languages (PHP, JavaScript, etc.), but the functions/method names differ.

1. Joining Strings

Joining takes a list (or iterable) of strings and combines them into a single string using a separator.

Syntax

separator.join(iterable)

Example

words = ["Python", "is", "fun"]
sentence = " ".join(words)
print(sentence)  # Output: Python is fun

More examples

"-".join(["2025", "11", "23"])         # "2025-11-23"
",".join(["apple", "banana", "mango"]) # "apple,banana,mango"

2. Splitting Strings

Splitting breaks a single string into parts based on a delimiter.

Syntax

string.split(separator)

Example

text = "Python is awesome"
parts = text.split(" ")
print(parts)  # Output: ['Python', 'is', 'awesome']

Split by comma

data = "apple,banana,mango"
data.split(",")  # ['apple', 'banana', 'mango']

Split by hyphen

date = "2025-11-23"
date.split("-")  # ['2025', '11', '23']

3. Splitting by Whitespace (No Separator)

If you call split() without an argument, it splits on any whitespace (spaces, tabs, newlines) and collapses multiple spaces.

text = "Python   is   amazing"
text.split()  # ['Python', 'is', 'amazing']

4. Re-joining After Split

You can split a string and re-join it with a different separator:

text = "apple-banana-mango"
parts = text.split("-")
new_string = ", ".join(parts)
print(new_string)  # Output: apple, banana, mango

5. Useful Patterns & Tips

When splitting CSV-like data, consider using a CSV parser to handle quoted fields.
Use str.split(maxsplit=n) to limit the number of splits.
For performance with many small concatenations, build a list and join() once (avoid repeated + on strings).
Trim whitespace before or after split with .strip() if needed.
In other languages: PHP uses explode() (split) and implode() / join() (join); JavaScript uses split() and array.join().

Summary Table

Operation	Python method	Example result
Join list	`"sep".join(list)`	`"a b"`
Split string	`str.split("sep")`	`["a","b"]`
Split by whitespace	`str.split()`	`["a","b"]`

Citations

🔗 View other articles about PHP:
http://savanka.com/category/learn/php/

🔗 External PHP Documentation:
https://www.php.net/manual/en/