Php break scripts and

Содержание

PHP break Statement
PHP: Tips of the Day
Break in PHP
Examples of Break in PHP
Example #1
Example #2
Example #3
Example #4
Example #5
Example #6
Conclusion
Recommended Articles
PHP: break, continue и goto
continue
goto

PHP break Statement

Sometimes a situation arises where we want to exit from a loop immediately without waiting to get back to the conditional statement.

The keyword break ends execution of the current for, foreach, while, do while or switch structure. When the keyword break executed inside a loop the control automatically passes to the first statement outside the loop. A break is usually associated with the if.

In the following example we test the value of $sum, if it is greater than 1500 the break statement terminate the execution of the code. As the echo statement is the first statement outside loop it will print the current value of $sum.

1500) < break; >$sum = $sum+$array1[$x1]; $x1=$x1+1; > echo $sum; ?>

PHP: Tips of the Day

How to Sort Multi-dimensional Array by Value?

Try a usort, If you are still on PHP 5.2 or earlier, you’ll have to define a sorting function first:

function sortByOrder($a, $b) < return $a['order'] - $b['order']; >usort($myArray, 'sortByOrder');

Starting in PHP 5.3, you can use an anonymous function:

And finally with PHP 7 you can use the spaceship operator:

usort($myArray, function($a, $b) < return $a['order'] $b['order']; >);

To extend this to multi-dimensional sorting, reference the second/third sorting elements if the first is zero — best explained below. You can also use this for sorting on sub-elements.

usort($myArray, function($a, $b) < $retval = $a['order'] $b['order']; if ($retval == 0) < $retval = $a['suborder'] $b['suborder']; if ($retval == 0) < $retval = $a['details']['subsuborder'] $b['details']['subsuborder']; > > return $retval; >);

If you need to retain key associations, use uasort() — see comparison of array sorting functions in the manual

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Break in PHP

PHP break statement is used to exit from a loop instantaneously without having to wait for getting back at the conditional statements like for loop, while loop, do-while, switch and for-each loop. If there are multiple loops present and the break statement is used, it exits only from the first inner loop. Break is present inside the statement block and gives the user full freedom to come out of the loop whenever required.

Web development, programming languages, Software testing & others

As shown above, the code first enters the conditional statement block once the condition for the loop is satisfied and continuously executes the statements in the loop until the condition is not satisfied. When a break statement is written in the code, as soon as the program encounters it the code exits from the current loop irrespective of whether the condition is satisfied or not as shown.

Examples of Break in PHP

Let us understand the working of a break statement by taking a few examples for each conditional statement in various scenarios and checking its behavior for the same.

Example #1

Break statement inside the “for” loop.

 echo $var; echo "\n"; > echo "For loop ends here" ; ?>

Here we are printing the numbers from 1 to 10 in the for loop by initializing 1 to variable “var”. “var” starts printing incremental numbers starting from 1 till it encounters the if loop condition. Here we are mentioning that the variable should come out of the loop once its value reaches 5. This is done using the break statement as shown. We can see the same in the output as we are printing “For loop ends here” once the break statement is executed and it comes out of for loop even if for loop condition is not satisfied. Hence the break statement comes out of the entire logic of all other iterations.

Example #2

This example is to check the functionality of the break statement in a while loop.

 echo ("Exited loop at variable value = $var" ); ?>

In the above program variable “var” is first initialized to 0 and using while loop we are incrementing its value by one and printing the same. We are writing an if condition wherein we are making the code to exit by using a break statement once the variable value equals 5. This break makes it exit from the current while loop even though the specified condition of incrementing variable until the value 10 is not met. We are displaying the variable value at which the loop is broken.

Example #3

Here we are implementing break statements in the foreach loop.

In this program, we are first declaring an array containing a collection of letters. Then by using a foreach loop, we are printing all the elements of the array one by one. An if the conditional statement is introduced to break the loop once the value of array pointer reaches the letter “E”. Hence on encountering break statement the code exits without printing the next letter in the array i.e. “F”.

Example #4

The most common application of break is in a switch statement which can be shown below.

This is the example of a simple switch statement where we are initializing the variable value to 1 at first. Then by the use of switch conditions, we are checking the variable value and printing it once the condition matches.

Example #5

Here let us see the working of a break statement when there are two or more loops (conditional statements).

 echo "\n"; > echo "\n Loop Terminated"; ?>

Here we are using 2 nested foreach loops and also showing a case of using “break 2” which breaks out of both the loops in contrast to the “break” statement which breaks out of only the inner loop.

We have declared two arrays array1 and array2 and we are displaying the values of array2 for each value of array1 until and unless the value of array1 is not equal to array2. Once the value in array1 becomes the same as array2 we are breaking both loops by making use of break 2 statement which prevents the code from executing any more statements.

Example #6

Here we shall see how to use break statements to come out of “n” number of loops (conditional statements).

 > > > > echo 'Loop has terminated and value of a = '.$a; ?>

eg6

The break statement followed by the number of loops that need to be exited from are used to terminate from “n” number of loops.

where n is the number of loops that need to be exited from the loop.

We are using 4 nested for loops for this purpose. Variables a, b, c, d is initialized respectively for each for loop and we are incrementing their values by 1. The same values are displayed in the output to understand its flow better. At last, we are giving a condition for all the 4 loops to break if the value of the first variable becomes equal to 3 which it eventually did and can be shown in the output. We are printing the loop has terminated at the end along with as value to note the break’s functionality.

Conclusion

When we are using one or more conditional statements in our code and we need to exit from the same at a particular point, we can use the break statement. Basically, it helps to terminate from the code when the condition we give falls TRUE. We can also pass an integer along with break to terminate from any number of existing loops instead of declaring the break again and again.

PHP: break, continue и goto

Часто бывает удобно при возникновении некоторых условий иметь возможность досрочно завершить цикл. Такую возможность предоставляет оператор break . Он работает с такими конструкциями как: while, do while, for, foreach или switch .

Оператор break может принимать необязательный числовой аргумент, который сообщает ему, выполнение какого количества вложенных структур необходимо завершить. Значением числового аргумента по умолчанию является 1, при котором завершается выполнение текущего цикла. Если в цикле используется оператор switch , то break/break 1 выходит только из конструкции switch .

\n"; break 1; /* Выход только из конструкции switch. */ case 10: echo "Итерация 10; выходим
\n"; break 2; /* Выход из конструкции switch и из цикла while. */ > > // другой пример for ($bar1 = -4; $bar1 < 7; $bar1++) < // проверка деления на ноль if ($bar1 == 0) < echo 'Выполнение остановлено: деление на ноль невозможно.'; break; >echo "50/$bar1 = ",50/$bar1,"
"; > ?>

Разумеется, иногда вы предпочли бы просто пропустить одну из итераций цикла, а не завершать полностью работу цикла, в таком случае это делается с помощью оператора continue .

continue

Для остановки обработки текущего блока кода в теле цикла и перехода к следующей итерации можно использовать оператор continue . От оператора break он отличается тем, что не прекращает работу цикла, а просто выполняет переход к следующей итерации.

Оператор continue также как и break может принимать необязательный числовой аргумент, который указывает на скольких уровнях вложенных циклов будет пропущена оставшаяся часть итерации. Значением числового аргумента по умолчанию является 1, при которой пропускается только оставшаяся часть текущего цикла.

"; continue; > echo "50/$bar1 = ",50/$bar1,"
"; > ?>

Обратите внимание: в процессе работы цикла было пропущено нулевое значение переменной $counter , но цикл продолжил работу со следующего значения.

goto

goto является оператором безусловного перехода. Он используется для перехода в другой участок кода программы. Место, куда необходимо перейти в программе указывается с помощью метки (простого идентификатора), за которой ставится двоеточие. Для перехода, после оператора goto ставится желаемая метка.

Простой пример использования оператора goto :

Оператор goto имеет некоторые ограничение на использование. Целевая метка должна находиться в том же файле и в том же контексте, это означает, что вы не можете переходить за границы функции или метода, а так же не можете перейти внутрь одной из них. Также нельзя перейти внутрь любого цикла или оператора switch . Но его можно использовать для выхода из этих конструкций (из циклов и оператора switch ). Обычно оператор goto используется вместо многоуровневых break .

"; > echo 'после цикла - до метки'; // инструкция не будет выполнена end: echo 'После метки'; ?>

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