I have a situation where I want to check if a lot of strings are empty before I perform an operation on them. I don't want to have to perform this check on every single string manually, so I put it in a function that looks like this:
function format_field($field_name, $format) {
$value = get_field($field_name);
if ($value != "") {
return $format;
}
return "";
}
A call to this function looks like this:
format_field('website', "<p><strong>Website:</strong>$value</p>");
I was hoping that by writing $value in the string passed to format_field() the value of $value would be expanded in the function before it got returned, but that doesn't seem to be the case.
Is this at all possible and I'm just going wrong?
I also know about sprintf(), but since $value can be referenced multiple times in the string it's less than ideal.
The problem with your code is that when passing "<p><strong>Website:</strong>$value</p>" as a function argument, the $value variable doesn't get substituted later in the function block.
So for example if you have $value = 'https://a.b.c'; the value of $format becomes "<p><strong>Website:</strong>https://a.b.c</p>"
What you could try, is substitute a placeholder, for example
pass "<p><strong>Website:</strong>{value}</p>" as the $format argument, then use something like that:
$format = "<p><strong>Website:</strong>{value}</p>";
$value = 'https://www.google.com';
echo preg_replace('#\{value\}#i', $value, $format);
which actually returns: <p><strong>Website:</strong>https://www.google.com</p>
Related
I have an interesting situation. I am using a form that is included on multiple pages (for simplicity and to reduce duplication) and this form in some areas is populated with values from a DB. However, not all of these values will always be present. For instance, I could be doing something to the effect of:
<?php echo set_value('first_name', $first_name); ?>
and this would work fine where the values exist, but $user is not always set, since they may be typing their name in for the first time. Yes you can do isset($first_name) && $first_name inside an if statement (shorthand or regular)
I am trying to write a helper function to check if a variable isset and if it's not null. I would ideally like to do something like varIsset('first_name'), where first_name is an actual variable name $first_name and the function would take in the string, turn it into the intended variable $first_name and check if it's set and not null. If it passes the requirements, then return that variables value (in this case 'test'). If it doesn't pass the requirements, meaining it's not set or is null, then the function would return '{blank}'.
I am using CodeIgniter if that helps, will be switching to Laravel in the somewhat near future. Any help is appreciated. Here is what I've put together so far, but to no avail.
function varIsset($var = '')
{
foreach (get_defined_vars() as $val) {
if ($val == $var) {
if (isset($val) && $val) {
echo $val;
}
break;
}
}
die;
}
Here is an example usage:
<?php
if (varIsset('user_id') == 100) {
// do something
}
?>
I would use arrays and check for array keys myself (or initialize all my variables...), but for your function you could use something like:
function varIsset($var)
{
global $$var;
return isset($$var) && !empty($$var);
}
Check out the manual on variable variables. You need to use global $$var; to get around the scope problem, so it's a bit of a nasty solution. See a working example here.
Edit: If you need the value returned, you could do something like:
function valueVar($var)
{
global $$var;
return (isset($$var) && !empty($$var)) ? $$var : NULL;
}
But to be honest, using variables like that when they might or might not exist seems a bit wrong to me.
It would be a better approach to introduce a context in which you want to search, e.g.:
function varIsset($name, array $context)
{
return !empty($context[$name]);
}
The context is then populated with your database results before rendering takes place. Btw, empty() has a small caveat with the string value "0"; in those cases it might be a better approach to use this logic:
return isset($context[$name]) && strlen($name);
Try:
<?php
function varIsset($string){
global $$string;
return empty($$string) ? 0 : 1;
}
$what = 'good';
echo 'what:'.varIsset('what').'; now:'.varIsset('now');
?>
I am having situation where i want to pass variables in php function.
The number of arguments are indefinite. I have to pass in the function without using the array.
Just like normal approach. Comma Separated.
like test(argum1,argum2,argum3.....,..,,.,.,.....);
How i will call the function? Suppose i have an array array(1,2,3,4,5) containing 5 parameters. i want to call the function like func(1,2,3,4,5) . But the question is that, How i will run the loop of arguments , When calling the function. I tried func(implode(',',array)); But it is taking all return string as a one parameters
In the definition, I also want the same format.
I can pass variable number of arguments via array but i have to pass comma separated.
I have to pass comma separated. But at the time of passing i don't know the number of arguments , They are in array.
At the calling side, use call_user_func_array.
Inside the function, use func_get_args.
Since this way you're just turning an array into arguments into an array, I doubt the wisdom of this though. Either function is fine if you have an unknown number of parameters either when calling or receiving. If it's dynamic on both ends, why not just pass the array directly?!
you can use :
$function_args = func_get_args();
inside your test() function definition .
You can just define your function as
function test ()
then use the func_get_args function in php.
Then you can deal with the arguments as an array.
Example
function reverseConcat(){
return implode (" ", array_reverse(func_get_args()));
}
echo reverseConcat("World", "Hello"); // echos Hello World
If you truely want to deal with them as though they where named parameters you could do something like this.
function getDistance(){
$params = array("x1", "y1", "x2", "y2");
$args = func_get_args();
// trim excess params
if (count($args) > count($params) {
$args = array_slice(0, count($params));
} elseif (count($args) < count($params)){
// define missing parameters as empty string
$args = array_pad($args, count($params), "");
}
extract (array_combine($params, $args));
return sqrt(pow(abs($x1-$x2),2) + pow(abs($y1-$y2),2));
}
use this function:
function test() {
$args = func_get_args();
foreach ($args as $arg) {
echo "Arg: $arg\n";
}
}
I'm not sure what you mean by "same format." Do you mean same type, like they all have to be a string? Or do you mean they need to all have to meet some criteria, like if it's a list of phone numbers they need to be (ddd) ddd-dddd?
If it's the latter, you'll have just as much trouble with pre-defined arguments, so I'll assume you mean you want them all to be the same type.
So, going off of the already suggested solution of using func_get_args(), I would also apply array_filter() to ensure the type:
function set_names() {
function string_only($arg) {
return(is_string($arg));
}
$names_provided = func_get_args();
// Now you have an array of the args provided
$names_provided_clean = array_filter($names_provided, "string_only");
// This pulls out any non-string args
$names = array_values($names_provided_clean);
// Because array_filter doesn't reindex, this will reset numbering for array.
foreach($names as $name) {
echo $name;
echo PHP_EOL;
}
}
set_names("Joe", "Bill", 45, array(1,2,3), "Jane");
Notice that I don't do any deeper sanity-checks, so there could be issues if no values are passed in, etc.
You can use array also using explode http://www.php.net/manual/en/function.explode.php.
$separator = ",";
$prepareArray = explode ( $separator , '$argum1,$argum2,$argum3');
but be careful, $argum1,$argum2, etc should not contain , in value. You can overcome this by adding any separator. $separator = "VeryUniqueSeparator";
I don't have code so can't tell exact code. But manipulating this will work as your requirements.
I am familiar with scope but have not used it much. I know how to change a variable's value inside of a function if I know what the variable name is by using GLOBAL $variableName in the function.
I'm writing a method that is passed 2 arguments. The first will accept an array that contains strings and the second will hold settings to do such as md5 for encrypting and trim to trim spaces.
Is there a way I can change the first argument's value inside the function? or do you know of a better method to accomplish this?
function _Edit($string, $rules)
{
#check if array
if(is_array($rules)!=TRUE)
{array_push($GLOBALS[debug], '<span class="error">_Edits second arguement must be an array</span>');}
if(is_array($string)!=TRUE)
{array_push($GLOBALS[debug], '<span class="error">_Edits first arguement must be an array</span>');}else
{
#loop through the strings
foreach ($string as $sk=>$sv)
{
#make changes based on rules
/* order of rules is important.
the changes will be made in the order the rules are sent */
foreach ($rules as $rv)
{
switch ($rv)
{
case 'md5':
//$string[$sk] = md5($sv);
//GLOBALS[$string][$sk] = md5($sv);
break;
}
}
}
}
}
If I understand right, you want to change the value of the first argument outside of the function from inside the function? for this you will have to pass by reference, or you can just return the updated array and overwrite the original value.
http://php.net/manual/en/language.references.pass.php
Why don't you return the array you eventually modified in your function?
So...
$my_array = _Edit($my_array, $rules);
And in your function you do:
function _Edit($string, $rules) {
... your code ...
... modify $string ...
return $string;
}
Ok, I'm looking into using create_function for what I need to do, and I don't see a way to define default parameter values with it. Is this possible? If so, what would be the best approach for inputting the params into the create_function function in php? Perhaps using addslashes?
Well, for example, I have a function like so:
function testing($param1 = 'blah', $param2 = array())
{
if($param1 == 'blah')
return $param1;
else
{
$notblah = '';
if (count($param2) >= 1)
{
foreach($param2 as $param)
$notblah .= $param;
return $notblah;
}
else
return 'empty';
}
}
Ok, so how would I use create_function to do the same thing, adding the parameters and their default values?
The thing is, the parameters are coming from a TEXT file, as well as the function itself.
So, wondering on the best approach for this using create_function and how exactly the string should be parsed.
Thanks :)
Considering a function created with create_function this way :
$func = create_function('$who', 'echo "Hello, $who!";');
You can call it like this :
$func('World');
And you'll get :
Hello, World!
Now, having a default value for a parameter, the code could look like this :
$func = create_function('$who="World"', 'echo "Hello, $who!";');
Note : I only added the default value for the parameter, in the first argument passed to create_function.
And, then, calling the new function :
$func();
I still get :
Hello, World!
i.e. the default value for the parameter has been used.
So, default values for parameters work with create_function just like they do for other functions : you just have to put the default value in the list of parameters.
After that, on how to create the string containing the parameters and their values... A couple of string concatenations, I suppose, without forgetting to escape what should be escaped.
Do you want to create an anonymous function? The create_function is used to create the anonymous functions. Otherwise you need to create function normally like:
function name($parms)
{
// your code here
}
If you want to use the create_function, here is the prototype:
$newfunc = create_function('$a,$b', 'return "ln($a) + ln($b) = " . log($a * $b);');
echo "New anonymous function: $newfunc\n";
echo $newfunc(2, M_E) . "\n";
// outputs
// New anonymous function: lambda_1
// ln(2) + ln(2.718281828459) = 1.6931471805599
I'm having the same problem, trying to pass an array to a created callback function... I think I'll create a temporary variable... It's ugly but I have better to do then torture myself with slashes, my code is already cryptic enough the way it is now.
So, to illustrate:
global $tmp_someArray;
$tmp_someArray = $someArray;
$myCallback = create_function(
'$arg1',
'
global $tmp_someArray;
// do stuff with $tmp_someArray and $arg1....
return($something);
'
);
I'm building a small abstract class that's supposed to make certain tasks easier.
For example:
$var = class::get('id');
would run check if there's pointer id in the $_GET, returning a string or array according to parameters. This should also work for post and request and maby more.
I'm doing it in the way there's function for all the superglobals. I'm using get as example:
get function gets a pointer as parameter, it calls fetchdata function and uses the pointer and "$_GET" as the parameters.
fetchdata is supposed to just blindly use the string it got as superglobal and point to it with the other param. Then check if it exists there and return either the value or false to get function, that returns the value/false to caller.
Only problem is to get the string work as superglobal when you don't know what it is. I did this before with a switch that checked the param and in case it was "get", it set $_GET to value of another variable. However I don't want to do it like that, I want it to be easy to add more functions without having to touch the fetchdata.
I tried $method = eval($method), but it didn't work. ($method = "$_GET"), any suggestions?
EDIT: Sorry if I didn't put it clear enough. I have a variable X with string value "$_GET", how can I make it so X gets values from the source described in the string?
So simply it's
$X = $_GET if X has value "$_GET"
$X = $_POST if X has value "$_POST"
I just don't know what value X has, but it needs to get data from superglobal with the same name than its value.
According to this page in the manual:
Note: Variable variables
Superglobals cannot be used as variable variables inside functions or class methods.
This means you can't do this inside a function or method (which you would be able to do with other variables) :
$var = '_GET';
${$var}[$key]
Instead of passing a string to fetchdata(), could you not pass $_GET itself? I think PHP will not copy a variable unless you modify it ('copy on write'), so this shouldn't use memory unnecessarily.
Otherwise there are only nine superglobals, so a switch-case as you have suggested isn't unreasonable.
You could do this with eval() if you really had to, something like:
eval('return $_GET;');
I think that would be unnecessary and a bad idea though; it is slow and you need to be extremely careful about letting untrusted strings anywhere near it.
Don't use eval. Just use reference.
//test value for cli
$_GET['test'] = 'test';
/**
* #link http://php.net/manual/en/filter.constants.php reuse the filter constants
*/
function superglobalValue($key, $input = null) {
if ($input === INPUT_POST)
$X = &$_POST;
else
$X = &$_GET;
return (isset($X[$key]) ? $X[$key] : false);
}
function getArrayValue(&$array, $key) {
return (array_key_exists($key, $array) ? $array[$key] : false);
}
//test dump
var_dump(
superglobalValue('test', INPUT_GET),
superglobalValue('test', INPUT_POST),
getArrayValue($_GET, 'test'),
getArrayValue($_POST, 'test')
);
$_GET, $_POST and $_REQUEST dont have any null values by default, only string or array. So I used isset there instead of array_key_exists.
Param order: I always put required params before optional when I can, and the data objects before the manipulation/subjective params. Thats why key is first param for superglobalValue and second param for getArrayValue.
I'm not quite sure what you're trying to achieve, but you could have a look at the __callStatic magic method
class example{
protected static $supers = array('GET', 'POST', 'SERVER', 'COOKIE');
public static function __callStatic($functionName, $arguments){
$index = arguments[0];
$desiredSuper = strtoupper($functionName);
if(in_array($desiredSuper, self::$supers)){
doStuff ( $_{$desiredSuper}[$index] );
}
else{
throw new Exception("$desiredSupper is not an allowed superGlobal");
}
}
}
you could then do:
example::get('id'); //wo do stuff to $_GET['id']
example::server('REQUEST_METHOD'); //Will do stuff to $_SERVER['REQUEST_METHOD']
example::foo('bar'); //throws Exception: 'FOO is not an allowed superGlobal'
Php manual on magic methods: http://ca.php.net/manual/en/language.oop5.overloading.php#language.oop5.overloading.methods
Edit
I just noticed your edit, you could try:
$X = {$X};
You can use $_REQUEST["var"] instead of $_GET["var"] or $_POST["var"].
A more complicated way would be to test if the variable exists in the GET array, if it doesnt then its POST. If it does its GET.
$var = null;
if (isset($_GET["varname"]))
{
$var = $_GET["varname"];
}
else
{
$var = $_POST["varname"];
}
If you want a variable to be accessible globally, you can add it tot he $GLOBALS array.
$GLOBALS['test']='test';
Now you can fetch $GLOBALS['test'] anywhere.