why in array single quotes not required according to the syntax

Question

I have some little confusion. I want to access the array as follows.

$_POST['un'];

or

  $arr['empno'];

But when I try in double quotes, it gives out a compile time error I tried the following:

 echo "welcome $_POST['un']";

in un i saved username by query string which is out of this question i think.. .so i write welcome i also tried

    echo "$array['emp']";

it also gives me an error. Whats the problem?

Add `{}` around the variable: echo `"welcome {$_POST['un']}";`. — Jite, Feb 27 '15 at 14:40
bro i know...but i want to use as i describe...sometimes i need this in my pages — Davinder kumar, Feb 27 '15 at 14:40
The brackets are needed when interpreting arrays. `echo "hi $name";` and `echo "hi {$name}";` Is basically the same, but the brackets are needed when calling a function/method (if i remember correctly) or an array. — Jite, Feb 27 '15 at 14:44
Answers given below, so you may as well pick the answer that best answered your question, in order to close it. Otherwise, it's still open. — Funk Forty Niner, Feb 27 '15 at 16:16

score 2 · Answer 1 · answered Feb 27 '15 at 15:02

2

When using double quotes in php strings you are telling php to interpret the string before printing it.
When using (associative) arrays or methods, you need to use the {} brackets around the value to make it work.

Simple variants, indexed arrays, etc. can be parsed by just using the double quotes, but when using associative arrays and methods, you will need the bracers.

More (and more in depth) info here: Php docs (strings)

echo "Some text... $array['key']";   // Bad
echo "Some text... {$array['key']}"; // Good
echo "Calling $var (simple) and {$var} (complex) is basically the same.";

If you want to do the 'cheapest' type, double quotes is not the way to go, rather go with concatenation and single quotes:

echo 'Some text... ' . $array['key'];

answered Feb 27 '15 at 15:02

Jite

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Even the [php docs in depth](https://www.php.net/manual/en/language.types.string.php#language.types.string.parsing) don't explain at all, why `echo "$array['key']"` is bad. – user31782 Nov 27 '21 at 17:57
Well, it's not "bad", it just doesn't work :P – Jite Dec 04 '21 at 18:53
Others are suggesting it does work, here: https://stackoverflow.com/a/70137669/3429430 – user31782 Dec 05 '21 at 09:50
No, in those cases they don't use any ' or " at all in the array accessor. Seems like that works as well. Personally, I use { } around all variables, makes it cleaner and easier to read imho. – Jite Dec 05 '21 at 17:53

score 1 · Answer 2 · edited Feb 27 '15 at 15:12

1

Further adding to Fred's comment, if you would like to use array variable, you can use it like:

echo "welcome $_POST[un]";

This will output the value of array variable

edited Feb 27 '15 at 15:12

André Ferraz

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answered Feb 27 '15 at 14:46

hemant

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Thanks for the mention, plus that's `not` my downvote, in case you may be wondering. – Funk Forty Niner Feb 27 '15 at 14:47
i also told...i already use it,,,,thats so i give title...read it agian title – Davinder kumar Feb 27 '15 at 14:48
You need to remove single quotes $_POST[un] – hemant Feb 27 '15 at 14:49
2

@Davinderkumar, you should have made that clear in the question, it is not clear in the title alone that you already know this syntax. I was actually going to post this answer before I saw it. – Antony D'Andrea Feb 27 '15 at 15:06

score 0 · Answer 3 · answered Feb 27 '15 at 15:04

0

Enclose the references to the array with { and }

echo "welcome {$_POST['un']}";

and

echo "{$array['emp']}";

answered Feb 27 '15 at 15:04

Outspaced

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why in array single quotes not required according to the syntax

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