quotes around array index?

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August 9th, 2002, 10:05 AM

cpv204

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quotes around array index?

I have a question about quoting array indices. This is from Rasmus Lerdorf's Programming PHP:

Quote:

You don't have to quote single-word strings. For instance, $age['Fred'] is the same as $age[Fred]. However, it's considered good PHP style to always use quotes, because quoteless keys are indistinguishable from constants. When you use a constant as an unquoted index, PHP uses the value of the constant as the index:

define('index',5);
echo $array[index]; // retrieves $array[5], not $array['index'];

You must use quotes if you're using interpolation to build the array index:

$age["Clone$number"]

So far so good.

Quote:

However, don't quote the key if you're interpolating an array lookup:

// these are wrong
print "Hello, $person['name']";
print "Hello, $person["name"]";
// this is right
print "Hello, $person[name]";

I understand why the 2nd example is wrong but why is the 1st example wrong?

August 9th, 2002, 11:59 AM

m0nk3y

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it could be the function print(), it might be weird, try echo or the print with the ()

anyways, i tried it, just change it to this:

PHP Code:


		
			
print "Hello, " . $person['name'];

works fine.

I dont think print likes two singles quotes, it doesnt like it

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August 9th, 2002, 12:53 PM

cpv204

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m0nk3y,

Thanks for your code, but I didn't need a workaround, because the correct way to do it is right there: print "Hello, $person[name]";.

By the way, echo "Hello, $person['name']"; doesn't work either.
Neither does print ("Hello, $person['name']");

I can see from trying the code myself that it doesn't work but I was a little curious as to why.

I can understand why the 2nd of Rasmus's examples doesn't work, because using the double quotes around the array's index closes the first double quote from before the Hello.

I was looking for a similarly intuitive reason for why echo "Hello, $person['name']"; is bad syntax.

If the answer is simply that's the way it is, I'll accept it.

August 9th, 2002, 01:30 PM

Donncha

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PHP just doesn't like you using quotes for array lookups without curly brackets, it's too complicated for it to parse.
So use either of the following: (btw it has nothing to do with print(), it's a string issue)
echo "blah $array[index] blah";
echo "blah {$array['index']} blah";
You can use curly braces for all sorts of complicated expressions...
echo "blah {$object->array['index']['subindex']} blah";

Have a look at http://www.php.net/manual/en/language.types.php , there's a lot of "Gee I didn't know that before" stuff in there.

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