Share My Trick: Automate an progressively growing string (of/for whatever you want)

[panamade]

Well I'm pretty green at this whole scripting business, but results so far have been pretty good.

I came up with the following simple technique out of necessity, and thought I'd share it, see what y'all think and if you already use it.

Here's my scenario- apply the concept to whatever you want:

I needed to generate a string of table column headings for an SQL SELECT statement.

My columns were named q1, q2, q3, q4... since you can't name columns simply as integers.

Anyway, in order to generate the string, I obviously needed to employ a loop, but what I figured out was that if I defined the variable name for the string as equal to itself plus the next entry in the series, it would progressively grow in length over the course of the loop's execution.

Like this:

for($i = 0; $i < 20; $i++)
{
$colq = $colq.' '.'q'.($i+1).',';
};

This results in $colq = q1, q2, q3, q4,... The only issue being an extra comma needing to be trimmed off the last column name; so all I did then was this:

$colsq = rtrim($colq,',');

Bingo bango.

I seem to use this a lot now. Maybe you can too. Or maybe it's all completely unnecessary cause there's a much easier way I'm unaware of. Who knows? Enjoy, and please let me know what you think.

-panamade

[rulian]

There are probably more "efficient" ways to do things almost at every level, but if you found a solution to your problem that works its an accomplishment. As we get more experienced with programming you always find better ways to do what you have done before so dont be surprised if it happens.

As for this specific problem you can handle it in a multitude of ways, once again go with what is most comfortable and makes most sense to you. If you simply need a string containing q1 - q-20 another approach could be

<?PHP
$Range=range(1,20); /// CREATES AN ARRAY CONTAINING A RANGE OF NUMBERS 1-20
foreach($Range as $Number) { $Q[] = "q".$Number; } /// WALKS THROUGH THE ARRAY ADDING A "q" TO EACH VALUE IN $Range AND CREATES A NEW ARRAY VARIABLE CALLED $Q
echo implode(",",$Q); /// IMPLODE COMBINES ALL ELEMENTS ON AN ARRAY USING A "GLUE", IN THIS CASE A COMMA
?>

The result is the same and probably no more streamline then your code but it's a way to become familiar with the different string and array functions in PHP