16.8.1. if

if(expr) {              if(expr):
  statements            statements
} elseif(expr) {      elseif(expr):
  statements            statements
} else {               else:
  statements           statements
}                        endif;

The if statement causes particular code to be executed if the expression it acts on is true. With the first form, you can omit the braces if you only need to execute a single statement.

16.8.2. switch

switch(expr) {         switch(expr):
  case expr:               case expr:
    statements              statements
    break;                    break;
  default:                  default:
    statements              statements
    break;                    break;
}                            endswitch;

The expression for each case statement is compared against the switch expression and, if they match, the code following that particular case is executed. The break keyword signals the end of a particular case; it may be omitted, which causes control to flow into the next case. If none of the case expressions match the switch expression, the default case is executed.

16.8.3. while

while(expr) {         while(expr):
  statements             statements
}                         endwhile;

The while expression is checked before the start of each iteration. If the expression evaluates to true, the code within the loop is executed. If the expression evaluates to false, however, execution skips to the code immediately following the while loop. Note that you can omit the curly braces with the first form of the while statement if you only need to execute a single statement.

It is possible to break out of a running loop at any time using the break keyword. This stops the current loop and, if control is within a nested set of loops, the next outer loop continues. It is also possible to break out of many levels of nested loops by passing a numerical argument to the break statement (break n) that specifies the number of nested loops it should break out of. You can skip the rest of a given loop and go onto the next iteration by using the continue keyword. With continue n, you can skip the current iterations of the n innermost loops.

16.8.4. do/while

do {
  statements
} while(expr);

Note that due to the order of the parts of this statement, there is only one valid syntax. If you only need to execute a single statement, you can omit the curly braces from the syntax. The break and continue statements work with this statement in the same way that they do with the while statement.

16.8.5. for

for(start_expr; cond_expr; iter_expr) {
  statements
}

for(start_expr; cond_expr; iter_expr):
  statements
endfor;

A for loop takes three expressions. The first is the start expression; it is evaluated once when the loop begins. This is generally used for initializing a loop counter. The second expression is a conditional expression that controls the iteration of the loop. This expression is checked prior to each iteration. The third expression, the iterative expression, is evaluated at the end of each iteration and is typically used to increment the loop counter. With the first form of the for statement, you can omit the braces if you only need to execute a single statement.

The break and continue statements work with a for loop like they do with a while loop, except that continue causes the iterative expression to be evaluated before the loop conditional expression is checked.

16.8.6. foreach

foreach(array_expression as $value) {
  statements
}

foreach(array_expression as $value):
  statements
endforeach;

This loops through the array_expression and assigns each value of the array to $value in turn. You can also get the key for each element with this syntax:

foreach(array_expression as $key=>$value) {
  statements
}