PHP variable within an echo?

Question

My WordPress site needs to have a different RSS feed on every page. In the short-term, I need to find a way to output an RSS feed with category = "2" (which will later become a number from different pages). I'm relatively new to PHP though.

Is there a way to get a variable echo'd WITHIN an echo?

I've tried:

<?php
$category = '2';
echo do_shortcode('[rssfeed cat="$category"]');
?>

and

<?php
$category = '2';
echo do_shortcode('[rssfeed cat='echo "$category"']');
?>

... But obviously they don't work. Can anyone suggest a work-around? Thanks

@Rohil_PHPBeginner...do_shortcode() needs to be echoed

rnevius
– rnevius

2014-12-19 11:26:03 +00:00
Commented Dec 19, 2014 at 11:26 — rnevius
– rnevius, Commented Dec 19, 2014 at 11:26
I was talking about other echo

Rohil_PHPBeginner
– Rohil_PHPBeginner

2014-12-19 11:26:43 +00:00
Commented Dec 19, 2014 at 11:26 — Rohil_PHPBeginner
– Rohil_PHPBeginner, Commented Dec 19, 2014 at 11:26

Rizier123 · Accepted Answer · 2014-12-19 10:24:26Z

4

You can just concatenate your strings like this:

$category = '2';
echo do_shortcode("[rssfeed cat='" . $category . "']");

answered Dec 19, 2014 at 10:24

Rizier123

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12 Comments

Lee Over a year ago

It's always best to break out of the echo function to include variables this way. +1

Lightness Races in Orbit Over a year ago

@Lee: What do you mean "break out of the echo function"?

Lee Over a year ago

@LightnessRacesinOrbit as in, like the example above rather than including the variable directly inside the echo string like echo "This is my string with $variable";

JohnG Over a year ago

Awesome - thanks very much. And thanks to all who suggested alternatives that work.

Rizier123 Over a year ago

@Lee That's why i made it like that :D I think you can spot it much better if you 'break' the echo statement with a concatenation and put the variable there

|

Tim · Accepted Answer · 2014-12-19 10:30:19Z

2

You can adapt your first attempt but swap the " and ' around - variables will be parsed if you use double quotes http://php.net/manual/en/language.types.string.php#language.types.string.parsing

<?php
$category = '2';
echo do_shortcode("[rssfeed cat='$category']");
?>

answered Dec 19, 2014 at 10:30

Tim

3261 silver badge7 bronze badges

4 Comments

Tim Over a year ago

@rnevius yeah I didn't see that until after I posted

rnevius Over a year ago

@LightnessRacesinOrbit ... how?

Lightness Races in Orbit Over a year ago

@rnevius: It directly answers the question, it is clear to a newcomer, and it is to-the-point. This is not "a ripoff" and the downvote is completely unwarranted. The PHP tag is odd.

Matt Gibson Over a year ago

Indeed. In particular, I wouldn't downvote an answer that seemed similar, or even identical, that was posted within a few minutes of another—people very often work on answers at the same time and produce very similar results. As to which is better—that's in the eye of the beholder, and there's usually room for more than one similar answer, as different people think in different ways.

Matt Gibson · Accepted Answer · 2014-12-19 10:25:22Z

1

Variable interpolation only happens between double quotes. But shortcodes can use either single or double quotes for their attributes, so if you put your quotes the other way around, it should just work:

<?php
$category = '2';
echo do_shortcode("[rssfeed cat='$category']");
?>

The PHP string now has double quotes, so $category will be interpolated to its value, and the attribute has single quotes, which will still work fine ("Shortcode macros may use single or double quotes for attribute values"), and not terminate the enclosing PHP string.

answered Dec 19, 2014 at 10:25

Matt Gibson

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Comments

JohnG · Accepted Answer · 2014-12-19 12:41:00Z

Rizier123's answer above worked great:

<?php 
$category = '2';
echo do_shortcode("[rssfeed cat='" . $category . "']");
?>

I actually needed to pull a value from each WordPress page through Advanced Custom Fields, using the_field(category). When I tried to do:

<?php
$category = the_field(category);
echo do_shortcode("[rssfeed cat='" . $category . "']");
?>

It didn't work - even though

echo $category;

produced the right value. Lots of suggested variations didn't work either - possibly this is a problem with Wordpress. I figured I needed to somehow pass a printed value of a variable into another variable, for it to work. For anyone trying to do what I was doing, a solution I found that worked is:

<?php
function abc(){
print the_field(category);
}
ob_start();
abc();
$category = ob_get_clean();
 echo do_shortcode("[rssfeed cat='" . $category . "']");
?>

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