The item 'reference' in the array is set to $array['fruit']. But no is value returned
$array = array(
'fruit'=>'apple',
'reference'=>$array['fruit']
);
example: echo $array['reference']; //the word apple should be displayed
How is this result achieved?
You are actually referencing the $array variable while creating it so it's normal it'll contain nothing.
This'll work but to be honest, it's kinda sketchy what you are doing.
$array = array('fruit' => 'apple');
$array['reference'] = $array['fruit'];
You will have to set it later, because $array isn't initialized yet while you're already assigning.
$array = array(
'fruit' => 'apple'
);
$array['reference'] = &$array['fruit'];
The ampersand will create a reference to the index fruit.
Hope this helped.
Use
$array = array();
$array['fruit'] = "apple";
$array['reference'] = $array['fruit'];
Related
Currently i have an array $newArr with some elements as shown in picture below. How do I know the last digit of the array index (highlighted in yellow)?
This is important because, if later I wanted to insert a new record into this $newArr array, I could just
$newArr[$the_variable_that_holds_the_last_digit + 1] = ['foo', 'bar'];
otherwise the whole array overwrite if
$newArr = ['foo', 'bar'];
I think you are looking for end pointer
$array = array(
'a' => 1,
'b' => 2,
'c' => 3,
);
end($array); // it will point to last key
$key = key($array); // get the last key using `key`
Assuming you have the numerically indexed array, the last index on your array is :
$last_index = count($newArr) -1;
if However your keys are not sequential, you can do this:
end($newArr);
$last_key = key($newArr);
I think you can try this
$array = end($newArr);
$last_index = key($array);//Its display last key of array
For more details, please follow this link.
If the only reason is to not overwrite the values you can use [] which means add new value.
$arr = [1,2,3,4];
var_dump($arr);
// incorrect way:
$arr = [1,2];
var_dump($arr);
//correct way
$arr = [1,2,3,4];
$arr[] = [1,2];
var_dump($arr);
See here for output: https://3v4l.org/ZTg28
The "correct way" will in the example above input a new array in the array.
If you want to add only the values you need to insert them one at the time.
$arr[] = 1;
$arr[] = 2;
well, i have 2 variables
$variable1 = "123";
$variable2 = "321";
both variables are calculated by other methods and may vary due to change of circumstances, now i want to put these values in a single array for displaying, what i want is something like this
$array = ($variable1, $variable2)
and print like(in IDE)
array([0]=>123 [1]=>321)
both 123 and 321 are representations of variable values.
i tried compact() function but it gave me something weird, i tried make these two variables an array with only one element and merge them into one array but in fact i have many variables and it's infeasible to do this for every one of them.....please show me how i can do it and explain in detail the mechanism behind it, thank you very much.
There are several ways to do what you want.
You can use one of examples below :
// Define a new array with the values
$array1 = array($variable1, $variable2);
// Or
$array2 = [$variable1, $variable2];
// Debug
print_r($array1);
print_r($array2);
// Define an array and add the values next
$array3 = array();
$array3[] = $variable1;
$array3[] = $variable2;
// Debug
print_r($array3);
// Define an array and push the values next
// http://php.net/manual/en/function.array-push.php
$array4 = array();
array_push($array4, $variable1);
array_push($array4, $variable2);
// Debug
print_r($array4);
Just use the array function to get the values into one array.
$var1 = "123";
$var2 = "321";
$array = array($var1,$var2);
var_dump($array); returns:
array (size=2)
0 => string '123' (length=3)
1 => string '321' (length=3)
Or another example on how you could do it is:
$array = array();
$array[] = myFunction(); //myFunction returns a value and by using $array[] you can add the value to the array.
$array[] = myFunction2();
var_dump($array);
Here is your answer
$variable1 = "123";
$variable2 = "321";
$arr =array();
array_push($arr,$variable1);
array_push($arr,$variable2);
echo '<pre>';
print_r($arr);
Hope this will solve your problem.
As you want to put these item in array
First you have to initialize a variable
$newArray = []
After that you have to store the value in array which can be done by this
$newArray[] = $variable1;
// OR BY
array_push($newArray, $variable1);
They both are same it push the data to the end of the array
So your code will be like this
$newArray = []
$newArray[] = $variable1;
$newArray[] = $variable2;
If you want to do it in loop then do somthing like this
$newArray = []
foreach($values as $value){
$newArray[] = $value;
}
If there is a fix value then you can do like this
$newArray = [$variable1, $variable2];
//OR BY
$newArray = array($variable1, $variable2);
Both are same
And to print the value use
print_r($newArray);
Hope this will help
I have created few different strings with similar names, and I would like to display them all.
However, I will need to do this dynamically, because I will adding more of them, later on.
These strings are called:
$group1
$group2
$group3
$group4
My idea is to somehow count them all, and then display them with for loop. I just need help with counting part.
Though arrays are definitely the superior and appropriate solution in this case, since you insist in the comments that separate variables are required, you can solve this using a while loop to check for the existence of such consecutively named variables, creating the variable names dynamically with {}.
For example:
$group1 = '123';
$group2 = '456';
$group3 = '789';
$i=1;
while ($string = ${'group'.$i}) {
echo $string;
$i++;
}
Note how ${'group'.$i} dynamically creates each variable name. Also, naturally this approach would fail if the variables are not named consecutively (e.g. if you have $group1 followed by $group3). As said, you should definitely use an array for this.
See a live demo
Associative arrays are designed exactly for this:
$arr = array(
"group1" => "string1",
"group2" => "string2",
"group3" => "string3",
"group4" => "string4",
);
Now to get the length of your array:
$num = count($arr);
To access the first element
$firstElement = $arr["group1"];
Alternatively you can use an indexed array (access elements by their position):
$arr = array("string1", "string2", "string3", "string4");
$firstElement = $arr[0];
$num = count($arr);
you can use this to count+loop
$arr=array();
$add_to=array_push($arr,$group1);
$add_to=array_push($arr,$group2);
$add_to=array_push($arr,$group3);
$add_to=array_push($arr,$group4);
//count
echo count($arr);
//loop
foreach($arr as $key=>$value){
echo $value;
}
If I have the following array. What would be the best way to add a element to list[] for the last element of $myArray[]? Note that list[] has numerical indexes (i.e. not associative). Thanks!
$myArray[] = array( 'name' => 'hello', 'list' => array() );
If $myArray is not associative
array_push($myArray[count($myArray)-1]['list'], 'new element');
or
$myArray[count($myArray)-1]['list'][] = 'new element';
with this method you change the position of the array pointer.
You can do it like this:
$last = array_pop($myArray); // remove last element of array
$last['list'][] = "new element"; // add element to array
$myArray[] = $last; // add changed last element again
$myArray[count($myArray)-1]['list'][]="something to go in 'list' array";//this shall append
//to the second dimension array with keyname 'list'
There is actually a more beautiful way (in my opinion):
$ref = &$myArray[];
$ref['list'][] = 'new item'
As you can see $ref - is reference to the last element of $myArray, so you can change the last element by changing $ref;
array_push function do that.
array_push()
So, I'm starting a new project and working with php for the first time.
I get that the average definition and functioning of arrays in php is actually pretty much a namevalue combo.
Is there some syntax, API, or other terminology for just a simple list of items?
I.e. inserting something like ['example','example2','example3','example4'] that I can just call based off their index position of the array, without having to go in and modify the syntax to include 0 => 'example', etc...
This is a very shortlived array so im not worried about long term accessibility
php arrays are simple to use. You can insert into an array like:
$array=array('a','b','c'.....);
Or
$array[]="a";
$array[]="b";
$array[]="c";
or
array_push($array, "a");
array_push($array, "b");
array_push($array, "c");
array_push($array, "d");
and call them by their index values:
$array[0];
this will give you a
$yourArray = array('a','b','c');
or
$yourArray[] = 'a';
$yourArray[] = 'b';
$yourArray[] = 'c';
will get you an array with integer index values instead of an associative one..
You still can use array as "classic" arrays in php, just the way you think.
For example :
<?php
$array = array("First", "Second", "Third");
echo $array[1];
?>
You can then add different values <?php $array[] = "Forth"; ?> and it will be indexed in the order you specified it.
Notice that you can still use it as an associative array :
<?php
$array["newValue"] = "Fifth";
$array[1] = "ReplaceTheSecond";
$array[10] = "";
?>
Arrays in PHP can either be based on a key, like 0 or "key" => "value", or values can just be "appended" to the array by using $array[] = 'value'; .
So:
$mine = array();
$mine[] = 'test';
$mine[] = 'test2';
echo $mine[0];
Would produce 'test';
Haven't tested the code.