I have created a class called Functions which stores 3 public variables ($var1, $var2, $var3). I have a for loop that creates an object of that class, that updates the variables of the class and then add that object to an array. However, when I try and access the array, I get an error "Undefined property: Functions::$InsertTextHere".
The strange thing is, it doesn't play the error if I check the array at [$i], only if I check anywhere else in the array that was created in a previous iteration. For example, the echo within the for loop will not spark the error however the echos outside the for loop will.
I am sorry if this is hard to understand, please let me know if it is.
class Functions{
public $var1 = "";
public $var2 = "";
public $var3 = "";
}
$file <---- Puts out about 14 different lines
$fileContentArray = array();
for($i = 0; count($file) > $i; $i++){
$var1 = "randomstuff1: " . $i;
$var2 = "randomstuff2: " . $i;
$var3 = "randomstuff3: " . $i;
$temp = new Functions();
$temp->$var1 = $var1;
$temp->$var2 = $var2;
$temp->$var3 = $var3;
$fileContentArray[] = $temp;
echo $fileContentArray[$i]->$var3; <--- Doesn't Give Errors
}
echo $fileContentArray[0]->$var3; <--- Gives Errors
echo $fileContentArray[1]->$var3; <--- Gives Errors
echo $fileContentArray[13]->$var3; <--- Doesn't give error, final entry in array
You shouldn't use "$" on the object properties (variable) unless you want variable variables
class Functions{
public $var1 = "";
public $var2 = "";
public $var3 = "";
}
$file <---- Puts out about 14 different lines
$fileContentArray = array();
for($i = 0; count($file) > $i; $i++){
$var1 = "randomstuff1: " . $i;
$var2 = "randomstuff2: " . $i;
$var3 = "randomstuff3: " . $i;
$temp = new Functions();
$temp->var1 = $var1;
$temp->var2 = $var2;
$temp->var3 = $var3;
$fileContentArray[] = $temp;
echo $fileContentArray[$i]->$var3; <--- Doesn't Give Errors
}
echo $fileContentArray[0]->var3; <--- Gives Errors
echo $fileContentArray[1]->var3; <--- Gives Errors
echo $fileContentArray[13]->var3; <--- Doesn't give error, final entry in array
Edit: please see this as referrences
http://www.php.net//manual/en/language.variables.variable.php
http://www.php.net//manual/en/sdo.sample.getset.php
Related
Want to create a php variable using text before and after the value of another variable.
variable variables. But have only seen examples of assignment with no text.
$vsBOA_W[]=$rows['vsBOA_W'];
// BOA = team 3-char abbreviation. Looking for something similar to above but insert 3-char abbreviations based on a input file.
$numOfTeams = 3; // Determined from external source
$teamAbbr = array("BOA","CAA","CHN"); // For simplicity for this example. This array would normally be created from an external source.
for($i=0; $i<$numOfTeams; $i++) { // I know I can use size of array instead of nunOfTeams. That's not the issue.
echo $teamAbbr[$i]."<br>"; // for testing
$$("vs".{'$teamAbbr[$i]'}."_W[]"} = $rows['$$("vs".{'$teamAbbr[$i]'}."_W"}']; // a total guess
}
I expect the end result to look like:
$vsBOA_W[]=$rows['vsBOA_W'];
for BOA
Update #2: I tried the following (breaking down each step) and get the same error on $$TeamWins assignment.
for($i=0; $i<$numOfTeams; $i++) {
echo $teamAbbr[$i]."<br>";
$TeamWins = 'vs' . $teamAbbr[$i] . '_W';
echo "TeamWins=$TeamWins<br>";
$TeamWinsHold = $rows[$TeamWins];
echo "TeamWinsHold=$TeamWinsHold<br>";
$$TeamWins[] = $TeamWinsHold;
}
Update #3:
for($i=0; $i<$numOfTeams; $i++) {
echo $teamAbbr[$i]."<br>";
$TeamWins = 'vs' . $teamAbbr[$i] . '_W';
echo "TeamWins=$TeamWins<br>";
$TeamWinsHold = $rows[$TeamWins];
echo "TeamWinsHold=$TeamWinsHold<br>";
${$TeamWins}[] = $TeamWinsHold;
}
foreach(${$TeamWins} as $value) {
echo "value=$value<br>"; // only displays last element or value assigned from above loop.
}
Update #4 (final):
$teamW = array();
$teamL = array();
for($i=0; $i<$numOfTeams; $i++) {
//echo $teamAbbr[$i]."<br>";
$teamWName = 'vs' . $teamAbbr[$i] . '_W';
$teamLName = 'vs' . $teamAbbr[$i] . '_L';
//echo "teamWName=$teamWName<br>";
//echo "teamLName=$teamLName<br>";
$teamW[$teamWName] = $rows[$teamWName];
$teamL[$teamLName] = $rows[$teamLName];
}
I don't quite understand the interplay with the rows in your example. But going by your guess assignment, you can always simplify, by forming the variable name upfront:
<?php
$rows = ['xFOOy'=>[], 'xBARy'=>[], 'xBAZy'=>[]];
$items = ['FOO', 'BAR', 'BAZ'];
foreach($items as $abbr)
{
$name = 'x' . $abbr . 'y';
${$name}[] = $rows[$name];
}
But, I'd say you'd be better off with a keyed array than variable variables, as it makes for easier inspection, and there is less chance of namespace clashes.
I'm trying to create a function to pick up words from a text file randomly, and no one here poblema. The problem arises when I try to verify if the user correctly inserts the words. Unfortunately, I always get a negative answer. From what I understood when called, the function can not save the contents into the variable that naturally remains empty.
<?php
function random_word() {
$dictionary = "dictionary.txt";
$word = file($dictionary);
$n = 0;
while ($n < 2) {
$n++;
$randomword = array_rand($word);
echo $word[$randomword];
}
}
$a = random_word();
echo "-----------------";
echo $a;
?>
If I try to check the $a variable it tells me that it is NULL. I'm sure the problem is the function but I know PHP shortly and I'm struggling to find the error.
You need to return something. Not sure if you want to return a string or an array but your code seems to be made for string.
<?php
function random_word() {
$dictionary = "dictionary.txt";
$word = file($dictionary);
$n = 0;
while ($n < 2) {
$n++;
$randomword = array_rand($word);
$returner .= $word[$randomword] . " ";
}
return trim($returner);
}
$a = random_word();
echo "-----------------";
echo $a;
?>
<?php
$my_array = array("hello","world","howareu");
$c = count($my_array);
for($i=0;$i<=$c;$i++){
$v = '$var'.$i;
$splited = list($v) = $my_array;
}
?>
input:
$my_array
But expected output:
if I echo $var0, $var1, $var2;
hello, world, howareu
How to create dynamic PHP variables based upon the array count and then convert them into a list as a string?
You do not need list for that. $$ will suit you perfectly.
$my_array = array("hello", "world", "howareu");
foreach ($my_array as $key => $val)
{
$a = 'var'.$key;
$$a = $val;
}
echo $var0,", ", $var1,", " $var2;
Take a look here - Variable variables
Added:
or if you need count and for
for ($i = 0; $i < count($my_array); $i++)
{
$a = 'var'.$i;
$$a = $my_array[$i];
}
echo $var0,", ", $var1,", " $var2;
Of course, this line echo $var0,", ", $var1,", " $var2; sucks and looks like crap :) But in order to receive EXACTLY what you want, you need to modify variables, output like I've wrote, or use some function like implode with grue ', '.
Updated:
But if you need just that output, why not to use simple implode(', ', $my_array) :)
it's a matter of the data you need to process...if it's pretty static, you don't need the second foreach() for example, since you compare the keys anyways...
foreach($datavalueas $resultdatakey=>$resultdatavalue){
if($resultdatakey== 'A'){
//stuff for a
}
if($resultdatakey== 'B'){
//stuff for b
}
}
would become
if(isset($datavalueas['A'])){
//stuff for a
}
if(isset($datavalueas['B'])){
//stuff for b
}
since the foreach uses copies of the array, which are pretty bad for the performance...
Assuming i got your question right, you could use something like:
$array = array( 'x', 'y', 'z' );
foreach ($array as $name )
$$name = rand(1,100);
var_dump($x);
the $$ is key here, the first $ implies the variable as the second $ is used as the identifier for the variable. In this case the value being iterated over in the array. Giving us 3 variables: $x, $y, $z.
-- edit:
the correct code, besides using extract():
<?php
$my_array = array("hello","world","howareu");
$c = count($my_array);
for($i=0;$i < $c;$i++){
$v = 'var'.$i;
$$v = $my_array[$i];
}
echo "$var0, $var1, $var2";
?>
You can create dynamic variables via variables variable as Mr.kovpack have stated here. In below code you can access the variables from 0 to $c-1(count of array) as per your comment to Mr.kovpack.
$my_array = array("hello","world","howareu");
$c = count($my_array);
for($i=0;$i<=$c-1;$i++){
${'var'.$i} = $my_array[$i]; //Dynamic variable creation
// $splited = list($v) = $my_array;
}
echo $var0.$var1.$var2;
or you could use like below:
$my_array = array("hello","world","howareu");
$c = count($my_array);
for($i=0;$i<=$c-1;$i++){
$a='var'.$i;
$$a = $my_array[$i];
}
echo $var0."-".$var1."-".$var2;
You can read more on it here
Is there a way to access a member of an object, by using its name as a string?
When I declare an array...
$array = array();
$array['description_en']="hello";
$array['description_fr']="bonjour";
then I access a member like this:
$lang="en"; //just to show my purpose. it will be dynamic
$description = $array['description_'.$lang];
Can I do the same thing for objects?
For example:
$obj->description_en="hello";
$obj->description_fr="bonjour";
How can I access $obj->description_.$lang ?
class test
{
public $description_en = 'english';
}
$obj = new test();
$lang = 'en';
echo $obj->{"description_".$lang}; // echo's "english"
You can see more examples of variable variables here.
You can use this syntax:
<?php
class MyClass {
public $varA = 11;
public $varB = 22;
public $varC = 33;
}
$myObj = new MyClass();
echo $myObj->{"varA"} . "<br>";
echo $myObj->{"varB"} . "<br>";
echo $myObj->{"varC"} . "<br>";
This way, you can access object variables as if they were entries in an associative array.
At first glance I think you can get what I'm trying to do. I want to loop though variables with the same name but with a numerical prefix. I also had some confusion about the kind of loop I should use, not sure if a "for" loop would work. The only thing is I can't wrap my head around how php could interpret "on the fly" or fabricated variable. Ran into some trouble with outputting a string with a dollar sign as well. Thanks in advance!
$hello1 = "hello1";
$hello2 = "hello2";
$hello3 = "hello3";
$hello4 = "hello4";
$hello5 = "hello5";
$hello6 = "hello6";
$hello7 = "hello7";
$hello8 = "hello8";
$hello9 = "hello9";
$hello10 = "hello10";
for ( $counter = 1; $counter <= 10; $counter += 1) {
echo $hello . $counter . "<br>";
}
It's generally frowned upon, since it makes code much harder to read and follow, but you can actually use one variable's value as another variable's name:
$foo = "bar";
$baz = "foo";
echo $$baz; // will print "bar"
$foofoo = "qux";
echo ${$baz . 'foo'}; // will print "qux"
For more info, see the PHP documentation on variable Variables.
However, as I already mentioned, this can lead to some very difficult-to-read code. Are you sure that you couldn't just use an array instead?
$hello = array(
"hello1",
"hello2",
// ... etc
);
foreach($hello as $item) {
echo $item . "<br>";
}
Try ${"hello" . $counter}
$a = "hell";
$b = "o";
$hello = "world";
echo ${$a . $b};
// output: world
You can use variable variables as:
for ( $counter = 1; $counter <= 10; $counter += 1) {
echo ${'hello' . $counter } , '<br>';
}
as I guess u not even need to declare $hello1 = "hello1". coz the $counter is incrementing the numbers by its loop.
<?php
for ( $counter = 1; $counter <= 10; $counter += 1) {
echo 'hello' . $counter . "\n";
}
?>
so this is enough to get the output as you want.
the output will be:-
hello1
hello2
hello3
hello4
hello5
hello6
hello7
etc...