for
for (expr1; expr2; expr3) statement The first expression (expr1) is evaluated (executed) once unconditionally at the beginning of the loop.
In the beginning of each iteration,
expr2 is evaluated. If it evaluates to
At the end of each iteration, expr3 is evaluated (executed).
Each of the expressions can be empty or contain multiple
expressions separated by commas. In expr2, all
expressions separated by a comma are evaluated but the result is taken
from the last part.
expr2 being empty means the loop should
be run indefinitely (PHP implicitly considers it as
Consider the following examples. All of them display the numbers 1 through 10:
Of course, the first example appears to be the nicest one (or
perhaps the fourth), but you may find that being able to use empty
expressions in
PHP also supports the alternate "colon syntax" for
for (expr1; expr2; expr3): statement ... endfor; It's a common thing to many users to iterate through arrays like in the example below.
The above code can be slow, because the array size is fetched on every iteration. Since the size never changes, the loop be easily optimized by using an intermediate variable to store the size instead of repeatedly calling count:
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