How to make simple php's foreach equivalent in Javascript? [duplicate] - php

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Closed 10 years ago.
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Loop through array in JavaScript
I want to make the equivalent of php's foreach in javascript. Because I don't really know the Javascript language, I'd like someone to rewrite this PHP code into the Javascript piece:
$my_array = array(2 => 'Mike', 4 => 'Peter', 7 => 'Sam', 10 => 'Michael');
foreach($my_array as $id => $name)
{
echo $id . ' = ' . $name;
}
Is that even possible to do in the Javascript language?

Answer 1

The closest construct is
a = { 2: 'Mike', 4: 'Peter', 7: 'Sam', 10: 'Michael' };
for(var n in a) {
console.log(n+'='+a[n]);
}

Answer 2

In JQuery, The $.each function is similar.
It allows you to iterate arrays using a callback function where you have access to each item:
var arr = ["one", "two", "three", "four", "five"];
$.each(arr, function(index, value) {
// work with value
});
For plain Javascript?
for (var key in obj) {
alert(key + ': ' + obj[key]);
}

Answer 3

For you exists two way.
First when data is in object (in example it is in my_list)
and second when data is exactly in array (in example it is my_array)
In any case you can use JavaScript For...In statement
Example:
<script type="text/javascript" charset="utf-8">
var data;
var my_list = {2:'Mike', 4:'Peter', 7:'Sam', 10:'Michael'};
var my_array = new Array();
my_array[2] = 'Mike';
my_array[4] = 'Peter';
my_array[7] = 'Sam';
my_array[10] = 'Michael';
data = '';
for(index in my_list) {
data += (index+'='+my_list[index]+"\n");
}
console.log(data);
data = '';
for(index in my_array) {
data += (index+'='+my_array[index]+"\n");
}
console.log(data);
</script>
In both cases console output will be:
2=Mike
4=Peter
7=Sam
10=Michael
Actually please read http://www.w3schools.com/js/js_loop_for_in.asp

Answer 4

See below url
foreach equivalent of php in jquery?
Or try it
If you want to iterate an object, I would recommend the JavaScript variant:
for (var key in obj) {
alert(key + ': ' + obj[key]);
}
You can also iterate objects in jQuery like this:
Note! Doing this is pretty pointless unless you think this syntax is much simpler to maintain. The below syntax has much more overhead than the above, standard JavaScript, for-loop.
$.each(obj, function (key, value) {
alert(key + ': ' + value);
});
To iterate arrays, this is how you do it in standard JavaScript (assuming arr is the array):
for (var i = 0, l = arr.length; i < l; i++) {
alert(i + ': ' + arr[i]);
}
To do it in jQuery, you can do it like this:
$.each(arr, function (index, value) {
alert(index + ': ' + value);
});