I have a nested for loop that creates a empty string value that represents a multidimensional array. Once the for loops have finished the result is something like this:
"[[0,0,0,0],[0,0,0,0]]"
I would like to add this to a multidimensional array within my code, how would i do this?
I have tried:
map = eval("[[0,0,0,0],[0,0,0,0]]");
but this does not produce the correct multidimensional array i am looking for.
I am looking to be able to use the array like this:
map[0][1] == 1;
Thanks
You could parse the string using JSON.parse() (MDN docu).
var str = "[[0,0,0,0],[0,0,0,0]]";
var map = JSON.parse( str );
However, in your example there is no entry equaling 1, so you requirement map[0][1] == 1 wont be fulfilled that way.
Related
I have the below JSON object array which I get back from the server. However while the server sends back the response the data is enclosed in "" and that then makes the javascript function thing this is a String and not an Array.
"[
[32.361346650846805,50.90932315437885],
[32.36743646734031,50.95189517586323],
[32.35467638118774,50.95876163094135],
[32.342494619322636,50.904516635824166],
[32.36279664436138,50.90039676277729],
[32.380194752587755,50.899023471761666],
[32.3648265962154,50.91481631844135],
[32.361346650846805,50.90932315437885]
]"
I just need to get the String into an array and use a for loop to iterate in the set of elements in the array. However since it is being treated a string it is not possible to iterate using a for loop.
any help?
You just need to run this through JSON.parse(), which is supported by almost all the JavaScript parsers:
console.log(JSON.parse(`[
[32.361346650846805,50.90932315437885],
[32.36743646734031,50.95189517586323],
[32.35467638118774,50.95876163094135],
[32.342494619322636,50.904516635824166],
[32.36279664436138,50.90039676277729],
[32.380194752587755,50.899023471761666],
[32.3648265962154,50.91481631844135],
[32.361346650846805,50.90932315437885]
]`));
Just beware that the JavaScript might not like having line-breaks in strings if you give them in source code. If the original string does have line-breaks, that's totally fine. That's why I have used a template literal here.
// Say you have your string here.
var str = `[
[32.361346650846805,50.90932315437885],
[32.36743646734031,50.95189517586323],
[32.35467638118774,50.95876163094135],
[32.342494619322636,50.904516635824166],
[32.36279664436138,50.90039676277729],
[32.380194752587755,50.899023471761666],
[32.3648265962154,50.91481631844135],
[32.361346650846805,50.90932315437885]
]`;
// Convert to array.
var arr = JSON.parse(str);
// Loop throught the array.
for (var i = 0; i < arr.length; i++)
console.log(arr[i]);
This is the array:
{"C8_235550":
{"listing":"aut,C8_235550_220144650654"},
"C8_231252":
{"listing":"aut,C8_231252_220144650654"}}
It was fetched with a GET request from a Firebase database using Google Apps Script.
var optList = {"method" : "get"};
var rsltList = UrlFetchApp.fetch("https://dbName.firebaseio.com/KeyName/.json", optList );
var varUrList = rsltList.getContentText();
Notice the .getContentText() method.
I'm assuming that the array is now just a string of characters? I don't know.
When I loop over the returned data, every single character is getting pushed, and the JavaScript code will not find key/value pairs.
This is the FOR LOOP:
dataObj = The Array Shown At Top of Post;
var val = dataObj;
var out = [];
var someObject = val[0];
for (var i in someObject) {
if (someObject.hasOwnProperty(i)) {
out.push(someObject[i]);
};
};
The output from the for loop looks like this:
{,",C,8,_,2,3,5,5,5,0,",:,{,",l,i,s,t,i,n,g,",:,",a,u,t,,,C,8,_,2,3,5,5,5,0,_,2,2,0,1,4,4,6,5,0,6,5,4,",},,,",C,8,_,2,3,1,2,5,2,",:,{,",l,i,s,t,i,n,g,",:,",a,u,t,,,C,8,_,2,3,1,2,5,2,_,2,2,0,1,4,4,6,5,0,6,5,4,",},}
I'm wondering if the array got converted to a string, and is no longer recognized as an array, but just a string of characters. But I don't know enough about this to know what is going on. How do I get the value out for the key named listing?
Is this now just a string rather than an array? Do I need to convert it back to something else? JSON? I've tried using different JavaScript array methods on the array, and nothing seems to return what it should if the data was an array.
here is a way to get the elements out of your json string
as stated in the other answers, you should make it an obect again and get its keys and values.
function demo(){
var string='{"C8_235550":{"listing":"aut,C8_235550_220144650654"},"C8_231252":{"listing":"aut,C8_231252_220144650654"}}';
var ob = JSON.parse(string);
for(var propertyName in ob) {
Logger.log('first level key = '+propertyName);
Logger.log('fisrt level values = '+JSON.stringify(ob[propertyName]));
for(var subPropertyName in ob[propertyName]){
Logger.log('second level values = '+ob[propertyName][subPropertyName]);
}
}
}
What you have is an object, not an array. What you need to do is, use the
Object.keys()
method and obtain a list of keys which is the field names in that object. Then you could use a simple for loop to iterate over the keys and do whatever you need to do.
I am looking for a solution to create a single multidimensional associate array in javascript.
What I have: I have a mysql database I am accessing with php and have an array containing all fields (key,value pairs) in a single record. Their are upwards of 30 fields in each record so I am looking for a dynamic solution.
In the html coding, there is a form that is used to update a specific record in the table. I am using a function call on each input to fill a javascript array by key and value. The keys are identical to the keys in the php array.
In the function I am doing a json_encode call on the php array to pull in the "old" data to make it accessible to javascript.
What works: I am able to create a dynamic javascript associate array from the new data coming from the input function calls. I have tested this out using an alert after each call to the function.
What I need: A method to change the javascript array to a multidimensional array, pulling in the old value and adding it to the new array tied to the original key.
This works:
var changes={};
function change(key,value) {
changes[key[value]]=value;
for (key in changes) {
alert('key: '+key+'... value: '+changes[key]);
}
}
this is along the lines of what I am looking for:
var changes={};
function change(key,value) {
var oldInfo = eval(<? echo json_encode($oldInfo); ?>); //this from the php array
changes[key[newValue]]=value;
changes[key[oldValue]]=oldInfo[key];
for (key in changes) {
alert('key: '+key+'... value: '+changes[key[newValue]]);
}
}
Can someone point me in the right direction?
To clarify:
My php array $oldInfo holds the old information from the table, for example:
{fName=>"charles",lName=>"madison", etc.}
The javascript array hold new information:
{fName=>"Charlie",lName=>"Madison", etc.}
I would like a new multidimentional array (PHP) (or object in JavaScript) that would look something like this:
{fName=>{"charles","Charlie"}, lName=>{"madison","Madison"}, etc.}
lName and fName would be the key fields that are synonymous to both the PHP array and the JavaScript object.
It's really unclear what you want, but there are a couple of serious flaws with your logic:
var changes={}; ///this one way of declaring array in javascript
No, it isn't. That's an Object, which is very different from an array.
eval(<? echo json_encode($oldInfo); ?>);
You don't need eval here. The output of json_encode is JSON, which is a subset of JavaScript that can simply be executed.
changes[key[value]]=value;
This is totally wrong, and still a single-dimensional array. Assuming key is an array, all you're doing is inverting the keys/values into a new array. If key looks like this before...
'a' => 1
'b' => 2
'c' => 3
... then changes will look like this after:
1 => 'a'
2 => 'b'
3 => 'c'
For a multidimensional array, you need two keys. You'd write something like changes[key1][key2] = value.
Your variable naming is wrong. You should never see a line that reads like this: key[value]. That's backwards. The key goes between the [], the value goes on the other side of the =. It should read something like array[key] = value.
RE: Your clarification:
This doesn't work: {fName=>{"charles","Charlie"},...}. You're confusing arrays and objects; Arrays use square brackets and implicit numeric keys (["charles", "Charlie"] for example) while Objects can be treated like associative arrays with {key1: "value1", key2: "value2"} syntax.
You want an array, where each key is the name of a property and each value is an array containing the old and new values.
I think what you want is actually quite simple, assuming the "value" you're passing into the function is the new value.
var changes = {};
var oldInfo = <?= json_encode($oldInfo) ?>;
function change(key, value) {
changes[key] = [ oldInfo[key], value ]
}
This :
changes[key[newValue]]
Should be:
changes[key][newValue]
What I need: A method to change the javascript array to a multidimensional array, pulling in the old value and adding it to the new array tied to the original key.
Use aliases for the numeric indices to do this:
var foo = ["Joe","Blow"];
var bar = ["joe","blow"];
var names = {};
foo.fname = foo[0];
bar.fname = bar[0];
foo.lname = foo[1];
bar.lname = bar[1];
names.fname = [foo.fname,bar.fname];
names.lname = [foo.lname,bar.lname];
I am looking for a solution to create a single multidimensional associate array in javascript.
What I have: I have a mysql database I am accessing with php and have an array containing all fields (key,value pairs) in a single record. Their are upwards of 30 fields in each record so I am looking for a dynamic solution.
In the html coding, there is a form that is used to update a specific record in the table. I am using a function call on each input to fill a javascript array by key and value. The keys are identical to the keys in the php array.
In the function I am doing a json_encode call on the php array to pull in the "old" data to make it accessible to javascript.
What works: I am able to create a dynamic javascript associate array from the new data coming from the input function calls. I have tested this out using an alert after each call to the function.
What I need: A method to change the javascript array to a multidimensional array, pulling in the old value and adding it to the new array tied to the original key.
This works:
var changes={};
function change(key,value) {
changes[key[value]]=value;
for (key in changes) {
alert('key: '+key+'... value: '+changes[key]);
}
}
this is along the lines of what I am looking for:
var changes={};
function change(key,value) {
var oldInfo = eval(<? echo json_encode($oldInfo); ?>); //this from the php array
changes[key[newValue]]=value;
changes[key[oldValue]]=oldInfo[key];
for (key in changes) {
alert('key: '+key+'... value: '+changes[key[newValue]]);
}
}
Can someone point me in the right direction?
To clarify:
My php array $oldInfo holds the old information from the table, for example:
{fName=>"charles",lName=>"madison", etc.}
The javascript array hold new information:
{fName=>"Charlie",lName=>"Madison", etc.}
I would like a new multidimentional array (PHP) (or object in JavaScript) that would look something like this:
{fName=>{"charles","Charlie"}, lName=>{"madison","Madison"}, etc.}
lName and fName would be the key fields that are synonymous to both the PHP array and the JavaScript object.
It's really unclear what you want, but there are a couple of serious flaws with your logic:
var changes={}; ///this one way of declaring array in javascript
No, it isn't. That's an Object, which is very different from an array.
eval(<? echo json_encode($oldInfo); ?>);
You don't need eval here. The output of json_encode is JSON, which is a subset of JavaScript that can simply be executed.
changes[key[value]]=value;
This is totally wrong, and still a single-dimensional array. Assuming key is an array, all you're doing is inverting the keys/values into a new array. If key looks like this before...
'a' => 1
'b' => 2
'c' => 3
... then changes will look like this after:
1 => 'a'
2 => 'b'
3 => 'c'
For a multidimensional array, you need two keys. You'd write something like changes[key1][key2] = value.
Your variable naming is wrong. You should never see a line that reads like this: key[value]. That's backwards. The key goes between the [], the value goes on the other side of the =. It should read something like array[key] = value.
RE: Your clarification:
This doesn't work: {fName=>{"charles","Charlie"},...}. You're confusing arrays and objects; Arrays use square brackets and implicit numeric keys (["charles", "Charlie"] for example) while Objects can be treated like associative arrays with {key1: "value1", key2: "value2"} syntax.
You want an array, where each key is the name of a property and each value is an array containing the old and new values.
I think what you want is actually quite simple, assuming the "value" you're passing into the function is the new value.
var changes = {};
var oldInfo = <?= json_encode($oldInfo) ?>;
function change(key, value) {
changes[key] = [ oldInfo[key], value ]
}
This :
changes[key[newValue]]
Should be:
changes[key][newValue]
What I need: A method to change the javascript array to a multidimensional array, pulling in the old value and adding it to the new array tied to the original key.
Use aliases for the numeric indices to do this:
var foo = ["Joe","Blow"];
var bar = ["joe","blow"];
var names = {};
foo.fname = foo[0];
bar.fname = bar[0];
foo.lname = foo[1];
bar.lname = bar[1];
names.fname = [foo.fname,bar.fname];
names.lname = [foo.lname,bar.lname];
I am passing a JSON object and an array to a Javascript function, but the array acts empty when I alert it unless I alert a specific value.
function myFunction(jsonObj, array){
alert(array['item1']['name']); //alerts "item1"
alert(array); // alerts "" (not [object] as I'd expect)
alert(array.join('')); // alerts ""
}
What am I missing?
I'm developing with phonegap on xcode and also using jQuery and Jquery Mobile
Seems like you are using an array with string indexes. That won't work well:
> var array = [];
> array['foo'] = 'bar';
> array.length
0
Use an object instead:
var obj = {};
obj['foo'] = 'bar';
Use arrays only with numeric indexes.
Use JQuery's map function.
You can traverse all items in array or JSON Object.
By the way, add console.log(array) to your code and in chrome web dev env, or in firebug check it's structure.
array can only have number as indexes , so as to use normal array functions like join
But , an associative array would be treated in the same way as a JSON object .
You can do the join in the associative array like this :
var temp=[];
temp['item']='hello ';
temp['item2']='world';
var joinedString="";
for( i in temp ){
console.log(temp[i];
joinedString+=temp[i];
}
alert(joinedString); // Prints hello world
Just use it like a map and use a foreach loop . Normal array functions like join , length and all won't work