`Concat`

It is often necessary to append one string to another in PHP. And sometimes we must append a string to the start of another (prepend).

With the concat operator, which is the period char, we can combine 2 strings. And with curly braces we can use formatting to combine a string with literals.

Example

This example program demonstrates how to combine strings together with the concat operator. It also uses curly braces in a format string to combine strings.

Step 1 We create a new string with no data in it. This is where the data we later append is placed.

Step 2 We append a single lowercase letter "x" to the string ten times. It is modified after each append in the for-loop.

Step 3 It is also possible to prepend a string. Here we place a string containing the word "Result" in front.

Step 4 We use curly braces to surround the result string inside of a pattern. This has a leading word, and a newline at the end.

// Step 1: create new empty string.
$result = "";

// Step 2: append the letter "x" ten times.
for ($i = 0; $i < 10; $i++) {
    $result .= "x";
}
echo $result . "\n";

// Step 3: append the string to a leading string.
$result = "Result: " . $result;
echo $result . "\n";

// Step 4: use curly braces to place the string inside another.
$result = "CAT: {$result}.\n";
echo $result;xxxxxxxxxx
Result: xxxxxxxxxx
CAT: Result: xxxxxxxxxx.

Implode, join

The implode and join functions "merge" the strings from an array together. They are the same function with different names.

Version 1 We call implode with a comma string argument. This results in a string with two comma delimiters in it.

Version 2 We can use implode with just an array argument. There are no delimiters used—the strings are mashed together.

Version 3 We test out the join() function, which is just an alias for implode() so no different in results is found.

$colors = ["blue", "orange", "green"];

// Version 1: combine with comma chars in between.
$result = implode(",", $colors);
var_dump($result);

// Version 2: no delimiter implode.
$result = implode($colors);
var_dump($result);

// Version 3: join is the same as implode.
$result = join(",", $colors);
var_dump($result);
string(17) "blue,orange,green"
string(15) "blueorangegreen"
string(17) "blue,orange,green"

Changing two strings into one is often done in PHP, and we have clear syntax for this operation. It is possible do this concatenation operation in a variety of ways.