Asked  2 Years ago    Answers:  5   Viewed   264 times

Something that really would like to know but never found out are shortcuts in PHP.

I am currently coding a function with a foreach loop with just a single statement inside. I tried to omit the curly braces as you can do in if/else control structures and it works. No errors.

foreach($var as $value)
    $arr[] = $value;

Now I tried to use it the same way but putting an if/else block inside it. Again, working and no errors.

foreach($var as $value)
    if(1 + 1 == 2) {
        $arr[] = $value;
    };

Then, I thought like "why is this working?" and omitted the closing semicolon. Still working. So I tried to use the if/else statement without curly braces inside the foreach loop and again, still working and no errors. But is the foreach loop really closed/ended right now?

foreach($var as $value)
    if(1 + 1 == 2)
        $arr[] = $value;

At least I omitted the closing semicolon again and (as expected) a parsing error occurred.

So my big question is: When can I omit the curly braces and in which structure/loop/function? I know that I can definitely do so in if and else. But what about while, for and foreach?

And yes, I know that it is not safe, smart, whatever to code without curly braces and there are shorthands like $condition ? true : false; and if: doSomething(); endif;, endfor; and endforeach;. I don't wanna learn about shorthands I just want to understand the conditions about when and where it is possible to omit the curly brackets.

 Answers

4

When you omit the braces it will only treat the next statement as body of the condition.

if ($x) echo 'foo';

is the same as

if ($x) { echo 'foo'; }

but remember that

if ($x)
  echo 'foo';
  echo 'bar';

will always print "bar"

Internally it's the other way around: if will only look at the next expression, but PHP treats everything in {} as a single "grouped" expression.

Same for the other control statements (foreach, and so on)

Friday, September 2, 2022
1

Had you previously traversed the array? each() remembers its position in the array, so if you don't reset() it you can miss items.

reset($array);
while(list($key, $value) = each($array))

For what it's worth this method of array traversal is ancient and has been superseded by the more idiomatic foreach. I wouldn't use it unless you specifically want to take advantage of its one-item-at-a-time nature.

array each ( array &$array )

Return the current key and value pair from an array and advance the array cursor.

After each() has executed, the array cursor will be left on the next element of the array, or past the last element if it hits the end of the array. You have to use reset() if you want to traverse the array again using each.

(Source: PHP Manual)

Wednesday, October 12, 2022
 
decpl
 
1

The problem with the first version is that if you go back and add a second statement to the if or else clauses without remembering to add the curly braces, your code will break in unexpected and amusing ways.

Maintainability-wise, it's always smarter to use the second form.

EDIT: Ned points this out in the comments, but it's worth linking to here, too, I think. This is not just some ivory-tower hypothetical bullshit: https://www.imperialviolet.org/2014/02/22/applebug.html

Saturday, September 10, 2022
5

Remove the semicolon at the end of this line:

if (temp > 95 || temp < 20);

And please, please use curly brackets! Java is not like Python, where indenting the code creates a new block scope. Better to play it safe and always use curly brackets - at least until you get some more experience with the language and understand exactly when you can omit them.

Wednesday, October 26, 2022
 
dudanf
 
2

The curly braces denote an object literal. It is a way of sending key/value pairs of data.

So this:

var obj = {name: "testing"};

Is used like this to access the data.

obj.name; // gives you "testing"

You can give the object several comma separated key/value pairs, as long as the keys are unique.

var obj = {name: "testing",
           another: "some other value",
           "a-key": "needed quotes because of the hyphen"
          };

You can also use square brackets to access the properties of the object.

This would be required in the case of the "a-key".

obj["a-key"] // gives you "needed quotes because of the hyphen"

Using the square brackets, you can access a value using a property name stored in a variable.

var some_variable = "name";

obj[ some_variable ] // gives you "testing"
Tuesday, November 29, 2022
 
sul
 
sul
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