variable-variables

Is there is a way to access variables using a variable string in python? For instance, I would like a neater way than using eval for the following: def toggleListButtons (self): buttons = ["flip", "remove", "removeAll", "delete", "deleteAll", "loadDirectory"] for button in buttons: eval("self." + button + "Button.setEnabled(!self." + button + "Button.isEnabled())") What you're looking for is the getattr() built-in function. There is also hasattr() and setattr() . button = getattr(self, 'flipButton') button.setEnabled(True) 来源： https://stackoverflow.com/questions/12111358/python-variable

I'm attempting to dynamically access both the $_GET and $_POST arrays, among others, using variable variables. The reason I'm trying to do this is so that I can perform similar actions on multiple arrays without needing to declare specific iterations for each. I'm reasonably sure this is possible, as PHP's documentation says it is able to use variable variables to dynamically access an array, however I'm unable to get it to work. A simple demonstration is when I'm attempting to verify that a certain property has been set. if(isset(${$this->_array}[$property])) { return ${$this->_array}[

I've been developing in PHP for a while now, and I still have not had a task where I've had to use variable variables. Can anyone give me examples where using them is a good idea ? Or were they included in the language just for fun ? One situation where I've had to use them is URI processing, although this technique might be dated, and I admittedly haven't used it in a long time. Let's say we want to pull the URI from the script in the format domain.tld/controller/action/parameter/s . We could remove the script name using the following: $uri_string = str_replace($_SERVER['SCRIPT_NAME'], '', $

I know you can do: $hash('foo') and $$foo and also $bar[$foo] , what are each of these things called? $hash('foo') is a variable function. $hash may contain a string with the function name, or an anonymous function. $hash = 'md5'; // This means echo md5('foo'); // Output: acbd18db4cc2f85cedef654fccc4a4d8 echo $hash('foo'); $$foo is a variable variable. $foo may contain a string with the variable name. $foo = 'bar'; $bar = 'baz'; // This means echo $bar; // Output: baz echo $$foo; $bar[$foo] is a variable array key. $foo may contain anything that can be used as an array key, like a numeric

Possible Duplicate: What's an actual use of variable variables? OK, this question may look a little bit point-whoreish, but I'd really like to know: when are variable variables useful? I haved programmed in PHP for several years, but I've never used them. For me it looks rather funny than useful. What are some real life examples of variable variables? Update: I'm really sorry about your votes. The linked 'duplicate' may be really a dupe except one thing: the examples listed there show me why not to use variable variables. Your Common Sense Never. This feature should be banned from the language

Ok so i have this php foreach loop <?php foreach ($step_count->rows as $step) { ?> and $step will be the step numbers 1, 2, 3, 4, 5 up to the total steps within the loop i a need to set the value of the images within the loop to standard_image_1 or whatever step there is...so for example <input value="<?php echo {$standard_image_"$step['number']"}; ?>" /> so basically i need the variable $standard_image_1 and so on depending on the steps but i dont know the correct syntax to do this Look at the docs for "variable variables" - http://php.net/manual/en/language.variables.variable.php <?php echo