which is best (cons/pros)

seby

i forget which is the best method:

$variable = 'this is my string';

// or

$variable = "this is my string";

what about echo:


echo "this is my $variable";

// or

echo 'this is my' . $variable;

also is it bad to do something like:

echo ('this is some text');

// or 

echo ("this is some text");

which is the best coding practice?

drag0n

Well it depends on what youe application does.. youll need different methods for different ways... such as if you want to put two things on one line such as a variable and text.. then you use
echo 'this is my' . $variable;
and if you want to do all variables just echo $variable and print is sometimes good for debugging like print_r etc... personally I have used every way you have described since you run into situations where one is not enough, so my advice would be to practice all of them 😉

sarahk

You are right that
$b = 'abc';
$a = "This is a variable: {$b}and it's great";

is the same as

$a = "This is a variable: $band it's great";

is the same as

$a = 'This is a variable: ' . $b . 'and it's great';

For safety the first option is best.
For readability go for the second option.
Probably all take the same amount of time to process.

In the example above I didn't leave a space between the variable name and the next word. That might be ok, but what if there was a variable $band. How would PHP know which to use? The {} tell PHP explicitly where a variable name begins and ends.

What you should be aware of are bits of code like:

$a = $HTTP_POST_VARS["name"];

which should be written as

$a = $HTTP_POST_VARS['name'];

as the double quotes tell PHP to expect a variable within the string and to expect to have to parse it. When there is none, then you are wasting time by asking PHP to look.

This answers your first example, where the single quotes are best.

Another thing I see quite often is code like

mail("$email", "$subject","$body");

which should just be

mail($email, $subject, $body);

as they are already strings and don't need to be double handled.

Jeb_

Originally posted by sarahk
You are right that
$b = 'abc';
$a = "This is a variable: {$b}and it's great";

is the same as

$a = "This is a variable: $band it's great";

Careful, that's not quite true. When PHP matches variables in a string, it does a 'greedy match'. Thus, it would not take $b from that 2nd string - it would take $b, and then all the characters to the first illegal character, which is the space. Thus, PHP would try matching the variable $band instead.

The two strings are quite different to PHP, but logically they make sense to us. If you're going to do something like that, you either need to escape out of the string, or wrap it in braces like your first example.

feldon23

For the best efficiency, use " " only when you are embedding strings and escapes like \n, \b, etc. Otherwise use ' '.

And if I am going to put variable names within my strings, I always wrap them in curly braces {}.

seby

thanx for the tips all.

Weedpacket

Originally posted by feldon23
For the best efficiency, use " " only when you are embedding strings and escapes like \n, \b, etc. Otherwise use ' '.

And if I am going to put variable names within my strings, I always wrap them in curly braces {}.

I did some experiments regarding the the speed of various methods:

There's no noticeable difference in speed between single-quoted and double-quoted strings when the latter doesn't contain any variables.

Double-quoted strings containing variables are significantly slower than strings (with either quotes) that don't contain variables; and, more importantly, slower than the equivalent method of concatenating strings with variables.

Heredoc-quoted strings I didn't look at. At a very rough guess I'd suspect them to be similar to double-quoted strings.

sarahk

Thanks Weedpacket!

I'm still living in phpV3-land so heredoc doesn't apply to me. A quick search on google came up with

http://shat.net/php/notes/heredoc.php

and this guy provides some test scripts which seem to prove that heredoc is faster.

One thing I do do when I'm writing echos in a function (for instance) is that I'll concatenate a string called $output and echo it in one hit, rather than 3 or 4.
I haven't tested it but I figure it's got to be better.