PHP if statement syntax
Contributed by qmchenry 
Tagged: PHP programming Examples of using the “if” command in PHP.
The simplest if statement executes command(s) if a condition evaluates as true:
if ($var > 0 ) {
// code here run if $var is positive
echo "Square root is: ".sqrt($var);
}
An optional else block can be added to execute code if the test condition evaluates as false. Multiple lines of code must be enclosed within { braces } while a single statement can be used in an if statement without braces.
if ($var >= 0 )
echo "Square root is: ".sqrt($var);
else {
$negvar = -1*$var;
echo "Square root is: ".sqrt($var)."i";
}
If statements can be nested:
if ($var < 10)
echo "var is less than 10";
elseif ($var < 20)
echo "var is between 10 and 20";
elseif ($var < 30)
echo "var is between 20 and 30";
else
echo "var is greater than 30";
A compact (if cryptic) shorthand is useful:
echo "var is ".($var < 0 ? "negative" : "positive");
is equivalent to:
echo "var is ";
if ($var < 0)
echo "negative";
else
echo "positive";
The shorthand can be considered (expression ? true_value : false_value) where 'expression' is evaluated and, if true, the 'true_value' is returned, otherwise the 'false_value' is returned.
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Tom Elders said on January 9, 2009
I think describing the ternary operator “?” as an if statement is a bit misleading. For example, inside a while loop:
while($row = mysql_fetch_row):
if($condition = true) { $something = $value }
endwhile;
that works. However, consider the following
while($row = mysql_fetch_row):
$something = ($condition = $true) ? $value : null;
endwhile;
If the condition is met, everything works fine, but on the next iteration of the loop, if the condition is not met, $something is set to null, which is probably not the desired effect 9 times out of 10.
peace love said on January 16, 2009
Thats a great shorthand, and gives good readability!
Sagar said on May 20, 2009
yes, ternary condition does give a problem
I would advise the following as well
while($row = mysql_fetch_row):
if($condition = true) { $something = $value }
endwhile;
Sagar said on May 20, 2009
My above suggestion is the same as what Tom Elders suggested. I support it
Name said on August 19, 2009
I am a novie in php programming.I was looking for “elseif” in php and this writ up heloped me to do it..
Thanking you
Anand V Mohan
davak said on August 22, 2009
Glad we could help!
php programming said on September 18, 2010
Done a excellent job in this blog, Alternatively create a great blog for the readers specially for PHP programming. Thanks.
bajick said on September 25, 2010
This is great!!! Nway, is there any way to shorthand the nested if statement?