A Quick Trim - PHP

If you're looking to perform a little cosmetic surgery on your strings, a good place to start is the family of trim() functions. The most useful of these, trim(), is constructed specifically to remove whitespace from the beginning and end of a string. This comes in handy if you need to remove whitespace from a value prior to using it elsewhere (a database insert, maybe?)

<?
$str = "       ever seen a white pigeon?";
// returns "ever seen a white pigeon?"
echo trim($str);
?>

It's also a good idea to use the trim() function on data entered into online forms, in order to ensure that your error-checking routines don't miss entries containing only whitespace. Here's an example which illustrates what I mean:

<?
$search = "       ";
// bad code, will not identify that search string
// actually contains nothing
if ($search != "")
{
perform_search();
}
// good code, will account for whitespace-only entries
if (trim($search) != "")
{
perform_search();
}
?>

You can also use the ltrim() and rtrim() functions, which remove whitespace from the beginning and end of a string respectively.

The next few string functions come in very handy when adjusting the case of a text string from lower- to upper-case, or vice-versa:

strtolower() - convert string to lower case strtoupper()- convert string to upper case ucfirst() - convert the first character of string to upper case ucwords() - convert the first character of each word in string to upper case

Here's an example:

<?
$str = "Something's rotten in the state of Denmark";
// returns "something's rotten in the state of denmark"
echo strtolower($str);
// returns "SOMETHING'S ROTTEN IN THE STATE OF DENMARK"
echo strtoupper($str);
// returns "Something's rotten in the state of Denmark"
echo ucfirst($str);
// returns "Something's Rotten In The State Of Denmark"
echo ucwords($str);
?>

You've already used the print() function extensively to display output. However, the print() function doesn't allow you to format output in any significant manner - for example, you can't write 1000 as 1,000 or 1 as 00001. And so the clever PHP developers came up with the sprintf() function, which allows you to define the format in which data is output.

Consider the following example:

<?
// returns 1.6666666666667
print(5/3);
?>

As you might imagine, that's not very friendly. Ideally, you'd like to display just the "significant digits" of the result. And so, you'd use the sprintf() function:

<?
// returns 1.67
echo sprintf("%1.2f", (5/3));
?>

A quick word of explanation here: the PHP sprintf() function is very similar to the printf() function that C programmers are used to. In order to format the output, you need to use "field templates", templates which represent the format you'd like to display.

Some common field templates are:

%s string
%d decimal number
%x hexadecimal number
%o octal number
%f float number

You can also combine these field templates with numbers which indicate the number of digits to display - for example, %1.2f implies that PHP should only display two digits after the decimal point. If you'd like the formatted string to have a minimum length, you can tell PHP which character to use for padding by prefixing it with a single quote (').

Here are a few more examples of sprintf() in action:

<?
// returns 00003
echo sprintf("%05d", 3);
// returns $25.99
echo sprintf("$%2.2f", 25.99);
// returns ****56
echo sprintf("%'*6d", 56);
?>

In addition to the sprintf() function, PHP also offers the strpad() function, which is used for padding strings to a specific length. This function accepts a string or string variable as argument, together with the minimum string length required; a couple of optional arguments allow you to also specify which character to use for padding, and the direction in which padding is to take place.

Here are a couple of examples:

<?
$str = "da bomb";
// returns "da bomb   "
echo str_pad($str, 10);
// returns "da bomb###"
echo str_pad($str, 10, "#");
// returns "***da bomb"
echo str_pad($str, 10, "*", STR_PAD_LEFT);
?>

Finally, the wordwrap() function can be used to break long sentences at a specified length.

<?
$str = "It's been ten years since Dr. Hannibal \"The Cannibal\" Lecter
(Anthony Hopkins) escaped from a maximum-security 
penitentiary - ten years in which he's roamed free, 
indulging his very specialized tastes. But out
of sight is very definitely not out of mind - he 
still haunts Clarice Starling (Julianne Moore), 
now a special agent in the FBI.";
// returns a word-wrapped block of width 50 characters
/*
It's been ten years since Dr. Hannibal "The
Cannibal" Lecter (Anthony Hopkins) escaped from a
maximum-security penitentiary - ten years in which
he's roamed free, indulging his very specialized
tastes. But out of sight is very definitely not
out of mind - he still haunts Clarice Starling
(Julianne Moore), now a special agent in the FBI.
*/
echo wordwrap($str, 50);
?>

>>> More PHP Articles          >>> More By Vikram Vaswani, (c) Melonfire

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