PHP string concatenation

Question

Is it possible to concatenate strings, as follows? And if not, what is the alternative of doing so?

while ($personCount < 10) {
    $result += $personCount . "person ";
}

echo $result;

It should appear like 1 person 2 person 3 person, etc.

You can’t use the + sign in concatenation, so what is the alternative?

You are actually using the "alternative" in your example code. — lanzz, Jul 11 '12 at 20:59
I find it hard to believe that no-one has pointed out that you are using "people" instead of "person". — Mark Gardner, Jul 04 '17 at 08:43
The bigger question is WHY does php use "." instead of "+" for string concatenation? I mean.. Seriously? — www-0av-Com, Mar 04 '18 at 00:14

score 99 · Accepted Answer · answered Jul 11 '12 at 20:59

99

Just use . for concatenating. And you missed out the $personCount increment!

while ($personCount < 10) {
    $result .= $personCount . ' people';
    $personCount++;
}

echo $result;

answered Jul 11 '12 at 20:59

abhshkdz

6,335
1
21
31

score 10 · Answer 2 · answered Jul 11 '12 at 21:03

10

One step (IMHO) better

$result .= $personCount . ' people';

answered Jul 11 '12 at 21:03

Loren Wolsiffer

167
10

score 7 · Answer 3 · answered Mar 18 '15 at 17:59

7

This should be faster.

while ($personCount < 10) {
    $result .= "{$personCount} people ";
    $personCount++;
}

echo $result;

answered Mar 18 '15 at 17:59

TurKux

105
1
3

4

Care to cite any evidence that `"{$personCount} people"` is faster than `$personCount . ' people'`? Otherwise it just seems like wild speculation... – Jake Dec 09 '17 at 23:33
PHP is forced to re-concatenate with every '.' operator. It is better to use double quotes to concatenate. – Abdul Alim Shakir Apr 05 '18 at 03:43
1

@Abdul Alim Shakir: But there is only one concatenation, so it shouldn't make any difference(?). – Peter Mortensen May 16 '21 at 09:48
Using `.` instead `.=` (the first instance) *does* affect performance (probably due to the [Schlemiel the Painter's algorithm](https://en.wikipedia.org/wiki/Joel_Spolsky#Schlemiel_the_Painter's_algorithm) - this can happen in *any* language or system), but it is ***already*** using `.=`. – Peter Mortensen May 16 '21 at 10:20
cont': From *[Assignment Operators](https://www.php.net/manual/en/language.operators.assignment.php)*: *"Using `$text .= "additional text";` instead of `$text = $text . "additional text";` can seriously enhance performance due to memory allocation efficiency. I reduced execution time from 5 seconds to 0.5 seconds (10 times) by simply switching to the first pattern for a loop with 900 iterations over a string $text that reaches 800K by the end."* – Peter Mortensen May 16 '21 at 10:26

score 6 · Answer 4 · answered Jul 12 '12 at 02:37

6

while ($personCount < 10) {
    $result .= ($personCount++)." people ";
}

echo $result;

answered Jul 12 '12 at 02:37

Farly Taboada

96
3

score 0 · Answer 5 · edited May 16 '21 at 09:42

0

I think this code should work fine:

while ($personCount < 10) {
    $result = $personCount . "people ';
    $personCount++;
}
# I do not understand why you need the (+) with the result.
echo $result;

edited May 16 '21 at 09:42

Peter Mortensen

30,738
21
105
131

answered Jul 11 '12 at 21:32

salim

11

5

See that you have `"people '` instead of `'people '`. – PhoneixS Jan 21 '14 at 11:55
1

You will probably get a load of errors because of what @PhoneixS has pointed out: mismatched quotes. – Mark Gardner Jul 04 '17 at 08:45

score 0 · Answer 6 · edited May 16 '21 at 09:51

0

$personCount = 1;
while ($personCount < 10) {
    $result = 0;
    $result .= $personCount . "person ";
    $personCount++;
    echo $result;
}

edited May 16 '21 at 09:51

Peter Mortensen

30,738
21
105
131

answered Aug 09 '18 at 06:31

Kavya Hanumantharaju

112
4

6

While this code may answer the question, providing additional context regarding how and/or why it solves the problem would improve the answer's long-term value. – Nic3500 Aug 09 '18 at 10:33

PHP string concatenation

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