CODEWITHSUNDEEP
phphtml
Tyler Jensen
Tyler Jensen

Reputation: 169

How do I turn my query result into a link?

I am returning data from three columns and displayed it with:

echo "<p><h3><span class='tyler'>".$results['COL 2']."</span></h3>".$results['COL 4'].$results['COL 3']."</p>";

This works fine. COL 4 is an actual URL and I am trying to put it in an anchor tag with COL 3 as the anchor text:

echo "<p><h3><span class='tyler'>".$results['COL 2']."</span></h3>""<a href=".$results['COL 4']"/>".$results['COL 3']."</a></p>";

I am trying to use this code but it doesn't work. My assumption is that the problem has something to do with the back to back quotes after the closing h3 tag. How would I go about making this work?

Upvotes: 0

Views: 52

Answers (1)

Nathaniel Ford
Nathaniel Ford

Reputation: 21220

It can get confusing to build large strings that are output to HTML. This is what you have:

echo "<p><h3><span class='tyler'>"
     .$results['COL 2']
     ."</span></h3>""<a href=".$results['COL 4']"/>"
     .$results['COL 3']
     ."</a></p>";

I've broken it up to more clearly reference what is going on. In the third line (starting with the close-span tag), you have two double quotes right next to each other. Further on, you have quotes opening the close-slash part of the tag, but not a string concatenation operator (.). Finally, you are confusing double and single quotes. You want:

."</span></h3><a href='".$results['COL 4']."'/>"

But a better way of doing this would be to split out your components:

$title = $results['COL 2'];
$href = $results['COL 4'];
$anchor_text = $results['COL 4'];
// Here you can add debugging statements to ensure you have the right values.

$paragraph = "<p><h3><span class='tyler'>%s</span></h3><a href='%s'>%s</a></p>"
echo sprintf($paragraph, $title, $href, $anchor_text);

This method uses sprintf to 'slot in' the strings you want. It allows you to be more clear about building the html, without worrying about what the specific 'dynamic' values are. There are, of course, many other ways of doing this sort of 'templating'.

An Aside on String Building in PHP

This line of code assigns a simple string to a variable in PHP:

$message = "Hello world!";

This line of code 'concatenates' three strings using the concatenation operator (which is a dot: .):

$html = "<p>".$html."</p>";

This line would yield an equivalent result:

$html = "<p>Hello world!</p>";

This line will yield an error:

$bad = "<p>""Hello world!""</p>";

The reason it yields an error is because the language will 'tokenize' the code into something like:

<variable name> <assign> <string> <string> <string> <end statement>

Except that, semantically, three <string>s in a row doesn't make sense. It needs an 'operator' between them, like so:

<variable name> <assign> <string> <concatenate> <string> <concatenate> <string> <end statement>

PHP knows how to 'parse' this string of tokens. It will know to evaluate each string, and then concatenate them together. An intermediate stage becomes this:

<variable name> <assign> <string (composed of three previous strings)> <end statement>

It knows this because the concatenation operator tells it how to combine those strings.

That brings us back to using the dot/concatenation operator:

$html = "<p>Hello world!</p>";

Now, HTML markup looks like this:

<a href="http://www.stackoverflow.com/help">SO Help Page</a>

And when PHP 'outputs' the final result, all it is doing is 'echo'ing or 'printing' a string to the HTML response. Given that, and given that PHP interprets a double quote as the 'end' of a string, how do you put strings into a variable, so it prints out like the HTML above? This won't work, because PHP doesn't know how to interpret http://... in this context:

echo "<a href="http://www.stackoverflow.com/help">SO Help Page</a>";

There are a few ways to get around this. You can 'escape' the double quotes:

echo "<a href=\"http://www.stackoverflow.com/help\">SO Help Page</a>";

By inserting a \ in the string before the double quote you signal to PHP to not end the string token, and to therefore parse the whole thing as a single string.

Alternatively, HTML also accepts single quotes for it's attribute values. So you can do this:

echo "<a href='http://www.stackoverflow.com/help'>SO Help Page</a>";

Which yields this on the HTML response:

<a href='http://www.stackoverflow.com/help'>SO Help Page</a>

Regardless of which way you go, you have to remember that the PHP code does not magically know that you're building an HTML page: it is simply constructing and printing strings to the HTML response. You have to tell it when to ignore parts of the string.

My point above is that for long enough PHP scripts, this can become confusing. So breaking down the strings into manageable chunks, so you can see what you're inserting and where things (like quotes, open and close tags, etc.) are makes your life easier.

Upvotes: 1

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