note 26101 added to language.variables.variable
| From: | info at gieson dot com | Date: | Fri, 18 Oct 2002 01:22:21 +0000 |
| Subject: | note 26101 added to language.variables.variable | ||
| Groups: | php.notes | ||
| Request: | Send a blank email to php-notes+get-38227@lists.php.net to get a copy of this message | ||
I needed to dynamically evaluate a varible.... i wanted to create the name of the variable on the
fly and then get it's value. In other words, I wanted to dynamically build the name of a
variable, and then evaluate it.
Example:
These items already exists:
$var1 = "bird";
$var2 = "cat";
$var3 = "dog";
... let's say there are 3 million of these variables in a series...
Now i want to find out which var has a value of "dog" - so i need to dynamically build the
name of the variable. You can do the FOR loop thing to create a string that represents the name of
the variable, but how on earth do you evaluate a string as if it were a variable? enter
"variable variables"
for ($i=0; $i<4; $i++){
//create the label of the variable;
$var_label_string = "var$i";
//Now evaluate that string as if it were a variable !;
$value_of_that_var = ${$var_label_string};
//now find out if that var is equal to "dog";
if ($value_of_that_var == "dog"){
print "Dog found here: $var_label_string";
}
}
--
http://www.php.net/manual/en/language.variables.variable.php
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