Converting an integer to a string in PHP

Question

Is there a way to convert an integer to a string in PHP?

Solution 1

You can use the strval() function to convert a number to a string.

From a maintenance perspective its obvious what you are trying to do rather than some of the other more esoteric answers. Of course, it depends on your context.

$var = 5;

// Inline variable parsing
echo "I'd like {$var} waffles"; // = I'd like 5 waffles

// String concatenation 
echo "I'd like ".$var." waffles"; // I'd like 5 waffles

// The two examples above have the same end value...
// ... And so do the two below

// Explicit cast 
$items = (string)$var; // $items === "5";

// Function call
$items = strval($var); // $items === "5";

Solution 2

There's many ways to do this.

Two examples:

 $str = (string) $int;
 $str = "$int";     

See the PHP Manual on Types Juggling for more.

Solution 3

$foo = 5;

$foo = $foo . "";

Now $foo is a string.

But, you may want to get used to casting. As casting is the proper way to accomplish something of that sort:

$foo = 5;
$foo = (string)$foo;

Another way is to encapsulate in quotes:

$foo = 5;
$foo = "$foo"

Solution 4

There are a number of ways to "convert" an integer to a string in PHP.

The traditional computer science way would be to cast the variable as a string:

$int = 5;
$int_as_string = (string) $int;
echo $int . ' is a '. gettype($int) . "\n";
echo $int_as_string . ' is a ' . gettype($int_as_string) . "\n";

You could also take advantage of PHP's implicit type conversion and string interpolation:

$int = 5;
echo $int . ' is a '. gettype($int) . "\n";

$int_as_string = "$int";
echo $int_as_string . ' is a ' . gettype($int_as_string) . "\n";

$string_int = $int.'';
echo $int_as_string . ' is a ' . gettype($int_as_string) . "\n";

Finally, similar to the above, any function that accepts and returns a string could be used to convert and integer. Consider the following:

$int = 5;
echo $int . ' is a '. gettype($int) . "\n";

$int_as_string = trim($int);
echo $int_as_string . ' is a ' . gettype($int_as_string) . "\n";

I wouldn't recommend the final option, but I've seen code in the wild that relied on this behavior, so thought I'd pass it along.

Solution 5

Warning: the below answer is based on the wrong premise. Casting 0 number to string always returns string "0", making the code provided redundant.

All these answers are great, but they all return you an empty string if the value is zero.

Try the following:

    $v = 0;

    $s = (string)$v ? (string)$v : "0";

View more solutions

Comments

[karim79]

So incredibly strange that we both picked 5. Also, + is java.

[jason]

I think you're mixing up your concatenation syntax between languages there.

[Frank Farmer]

I'd lean toward casting, simply because it makes your intentions abundantly clear. Casting has one and only one purpose: to change types. The other examples may almost look like mistakes, in some contexts.

[Chris Thompson]

Good point. I threw in some mysql_escape_string functions in there to clean it up.

[Admin]

$foo = 5; $foo = "$foo" extremely waistfull for memory in PHP use ''.

[Kzqai]

edited since mysql_escape_string is deprecated since it ignores charset.

[Yash Kumar]

Here is a live version - link

[freaky]

if we have those values, then will it be 55 or 10?

[Chris Thompson]

@freaky: $var + $var = 10, $var . $var = "55". "." is the string concatenation operator while "+" is the addition operator.

[chacham15]

@Kzqai for anyone who looks at this example to try and avoid injection attacks, I'd say abandon your attempts at escaping strings and use prepared statements

[Chris Thompson]

After 5 years I finally removed the SQL example as it was unnecessary to answer the question and introduced confusion.

[Kim Hogeling]

Here is a benchmark, for the examples in the answer: leifw.wickland.net/2009/08/…

[Admin]

Note that the question specifically says 'converting an integer', not a float. :)

[itsjavi]

"in most cases PHP will decide whats good for you" amazing :,)

[Elzo Valugi]

I don't think that PHP will coerce an integer to string all the time. It will do it for strlen(12345); but not for $x = 12345; echo $x[2]; All these casting functions are quite useful and lots of programmers are checking their types more and more.

[mindsupport]

How is about 0 as string ? $var =0;

[danielson317]

Warning!! If you pass in certain numbers php will round them when converting to string: strval(0.999999997) returns 1.

[nintyfan]

Correct the mistake, please. The correct form should be: $s = (string)$v ? (string)$v : "0";

[Peter Mortensen]

Re "string": literally or the type? Or something else? Can you make it more clear (by editing your answer)?

[Kaushik shrimali]

Thanks for the comment@ Peter Mortensen That is the return type "STRING" means your value should be converted as a string in a new variable. so that's why I edited string

[Marwan Salim]

The trim() function removes whitespace and other predefined characters from both sides of a string Although it returns string it's a bad practice. It's better to use strval() or number_format() perhaps.

[Lacek]

var_dump((string)0); prints string(1) "0" on PHP 5.5.9 (Released: 6 Feb 2014) for me. Which version of PHP did you get "an empty string if the value is zero"?

[JEX]

What do you mean by wasteful? ``` $foo = 5; $foo = "$foo"; ``` This code is just overwriting int value with string, of course, it's not the answer but what's wasteful?

[ADJenks]

Can anyone provide a reason to choose a cast over a function call or vice versa?

[Admin]

As it’s currently written, your answer is unclear. Please edit to add additional details that will help others understand how this addresses the question asked. You can find more information on how to write good answers in the help center.

[Your Common Sense]

It doesn't seem like an answer but rather a question.