I'm running into some trouble with a very simple mapreduce, I can't figure out what I've done wrong. I'm trying to merge two collections together, and this first, db.Pos looks like this
"chr" : "chr1", "begin" : 39401, "end" : 39442
The other collection, db.Gene has the following format
"chr" : "chr1", "begin" : 39401, "end" : 39442, "gene" : "GENE1"
My code looks like this:
var mapPos = function(){
emit({chr: this.chr, begin:this.begin, end:this.end},{gene:""});
}
var mapGene = function() {
emit({chr: this.chr, begin:this.begin, end:this.end},{gene:this.gene});
}
r = function(key,values){
var result = {gene:""}
values.forEach(function(value){
result.gene = value.gene;
});
return result;
}
res = db.Pos.mapReduce(mapPos, r, {out: {reduce: 'joined'}});
res = db.Gene.mapReduce(mapGene, r, {out: {reduce: 'joined'}});
So what I'd like to see is a collection where entries that are matching by chr, begin, and end are merged and the gene field is filled in from the db.Gene collection.
Instead, I'm getting the "gene" field in my "joined" collection updated to something other than 0 even when there is no matching doc in db.Gene that has a gene field.
What did I do wrong?
After reflexion, i think you should use merge and not reduce for your out.
The reason why you don't have the good value :
The problem is when the reduce is applied between the joined collection content and the result of the db.Gene.mapReduce.
The function reduce don't know which value is the newest, so the result.gene returned is the last value.gene of the values array.
To distinguish the value that will override the value existing in the collection, you can add a flag.
res = db.Pos.mapReduce(
function() {
emit({chr: this.chr, begin:this.begin, end:this.end},{gene:this.gene || ''});
},
function(key,values){
var result = {};
values.forEach(function(value){
if (value)
result.gene = value.gene;
});
},
{out: {reduce: 'joined'}}
);
res = db.Gene.mapReduce(
function() {
//Add a flag override here
emit({chr: this.chr, begin:this.begin, end:this.end},{gene:this.gene || '', override: true});
},
function(key,values){
var result = {};
values.forEach(function(value){
if (value.override)
result.gene = value.gene;
});
return result;
},
{out: {reduce: 'joined'}}
);
Hope it's clear :)
Related
I don't know what's wrong with the code. it works fine and both array have data. but i don't understand why the output found undefined from var _city array as it passed data to the city field.
How can I fix this?
var city = {
_country : _city
};
I'm wondering what you read that made you possibly believe that by writing what you did you would magically have an object keyed with one array with values from a second...
Essentially what is happening when you did when you
var city = {
_country : _city
};
is create an object that looks like
var city = {
'_country' : ['your', 'array', 'of', 'cities']
};
that is to say, an object with one key, '_country' mapped to an array of cities.
This explains why you get undefined... city['any string that isn't exactly " _country"'] == undefined
What you want to do is more likely,
var city = _country.reduce(function(acc, cur, idx) { acc[cur] = _city[idx]; return acc; }, {});
It's because _country is already defined above:
var _country = ["Afghanistan","Bahrain","Canada","Denmark","Ethiopia","France","Germany","Hong Kong","India","Japan"];
Change the definition within city to something else (maybe country):
var city = {
country: _city,
};
And it'll work.
I am using two different array object initialPermissionArr[item.id] and newPermissionArr[roleId] in two different functions
function(item){
vm.initialPermissionArr[item.id] = item.permissions.map(function (permission) {
permission.status = true;
return permission;
});
}
staticArr[item.id] = item.permissions.map(function (permission) {
permission.status = true;
return permission;
});
newpermissionArr[item.id] = vm.initialPermissionArr[item.id];
Below function updates the array, if same object is found it updates the status and if new object is found it pushes to newPermissionArr
function onChanageOfPermission(roleId,item) {
var flag = false ;
for (var key in newpermissionArr[roleId]){
if(newPermissionArr[roleId][key].id == item.id){
flag = true;
newPermissionArr[roleId][key].status = item.status;
break;
}
}
if (!flag) {
newPermissionArr[roleId].push(item);
}
}
So when newPermissionArr[roleId][key].status = item.status; is updated it also update the status in the initialPermissionArr[item.id] also.
And initial declaration is
var newPermissionArr = [];
var staticArr = [];
where for eg item is
{
roleId : 1,
permissions : [{"name": "A", "id" : 1},{ "name" : "B", "id" : 2 }]
}
I need initial object Array to remain same and at the end i need to compare the initial array with the modified array and need to find the reference however on updating the status it updates in both array. How to avoid this ?
The arrays reference the same object. To modify just one of them, you should use slice() function for clone the array:
newpermissionArr[item.id] = vm.initialPermissionArr[item.id].slice();
This is happening because of following line of code
newpermissionArr[item.id] = vm.initialPermissionArr[item.id];
Here object is passed by reference, so whenever newpermission is updated intialpermission will also be updated.
To fix this just copy the intialPermissionArr to newPermissionArr.
Unfortunately,plain javascript does not have any function like angular.copy. So you will have to do this in following way-
newrPermissionArr[item.id] = JSON.parse(JSON.stringify(vm.intialPermissionArr[item.id]));
this should fix your problem.
When you assign something to a and b and it is a pointer in memory to object c. Then as soon as you change it to c2 both a and b will get c2 from that point as they were just pointers to same location.
I have got the following JSON as an array and I am trying to filter on roles attribute but I am not able to filter the results. Please help me.
var data = [{"roles":["citysupervisor"]},{"roles":["partner","supervisor"]},{"roles":["CitySupervisor"]},{"roles":["citysupervisor"]},{"roles":["partner"]},{"roles":["citysupervisor"]},{"roles":["partner","supervisor"]},{"roles":["clientsupervisor"]}];
The JavaScript code which I wrote is below:
var results = data.filter(function(user) {
var roles = user.roles;
return roles.filter(function(role) {
return role == 'clientsupervisor';
});
});
Your data variable has a syntax error. You need to remove the quotes that are wrapping it.
Also a little change in your filtering code.
Change from this:
"[{"roles":["citysupervisor"]},{"roles":["partner","supervisor"]},{"roles":["CitySupervisor"]},{"roles":["citysupervisor"]},{"roles":["partner"]},{"roles":["citysupervisor"]},{"roles":["partner","supervisor"]},{"roles":["clientsupervisor"]}]";
To this:
[{"roles":["citysupervisor"]},{"roles":["partner","supervisor"]},{"roles":["CitySupervisor"]},{"roles":["citysupervisor"]},{"roles":["partner"]},{"roles":["citysupervisor"]},{"roles":["partner","supervisor"]},{"roles":["clientsupervisor"]}];
See it working:
var data = [{"roles":["citysupervisor"]},{"roles":["partner","supervisor"]},{"roles":["CitySupervisor"]},{"roles":["citysupervisor"]},{"roles":["partner"]},{"roles":["citysupervisor"]},{"roles":["partner","supervisor"]},{"roles":["clientsupervisor"], "name": "Jack", "profileId": 34533}];
var results = data.filter(function (user){
return user.roles.indexOf('clientsupervisor') > -1;
});
console.log(results);
try this, simple way
var results = data.filter(function(user) {
return user.roles.indexOf("clientsupervisor") > -1 ? true: false
});
and remove "" from data object, this is array object
var data = [{"roles":["citysupervisor"]},.....];
I'm trying to simply replace the invalid date with an empty string. I'm iterating through an array of objects, but whenever I try to use _.each() I get lost. If someone could show me a way to iterate through all the fieldsToCheck items in my list, that would be rad.
massage.removeBadDates = function(data){
var fieldsToCheck = [
"partsLeadTime",
"statusDate",
"targetDate",
"revisedTargetDate",
"quoteDate",
"dispositionDate",
"serviceDate",
"finalDate",
"receivedDate"]
var newData = []
_.map(data, function(value, index, list){
newData.push(value)
//single
if (list[index].partsLeadTime == "1900-01-01T00:00:00"){
newData[index].partsLeadTime = ""
}
});
return newData
};
You pretty much want something like this:
_.each(fieldsToCheck(function(field) {
if (list[index][field] == "1900-01-01T00:00:00") {
newData[index][field] = ""
}
});
I have the following JSON -
{
"node1":[
{
"one":"foo",
"two":"foo",
"three":"foo",
"four":"foo"
},
{
"one":"bar",
"two":"bar",
"three":"bar",
"four":"bar"
},
{
"one":"foo",
"two":"foo",
"three":"foo",
"four":"foo"
}
],
"node2":[
{
"link":"baz",
"link2":"baz"
},
{
"link":"baz",
"link2":"baz"
},
{
"link":"qux",
"link2":"qux"
},
]
};
I have the following javascript that will remove duplicates from the node1 section -
function groupBy(items, propertyName) {
var result = [];
$.each(items, function (index, item) {
if ($.inArray(item[propertyName], result) == -1) {
result.push(item[propertyName]);
}
});
return result;
}
groupBy(catalog.node1, 'one');
However this does not account for dupicates in node2.
The resulting JSON I require is to look like -
{
"node1":[
{
"one":"foo",
"two":"foo",
"three":"foo",
"four":"foo"
},
{
"one":"bar",
"two":"bar",
"three":"bar",
"four":"bar"
}
],
"node2":[
{
"link":"baz",
"link2":"baz"
},
{
"link":"qux",
"link2":"qux"
},
]
};
However I cannot get this to work and groupBy only returns a string with the duplicates removed not a restructured JSON?
You should probably look for some good implementation of a JavaScript set and use that to represent your node objects. The set data structure would ensure that you only keep unique items.
On the other hand, you may try to write your own dedup algorithm. This is one example
function dedup(data, equals){
if(data.length > 1){
return data.reduce(function(set, item){
var alreadyExist = set.some(function(unique){
return equals(unique, item);
});
if(!alreadyExist){
set.push(item)
}
return set;
},[]);
}
return [].concat(data);
}
Unfortunately, the performance of this algorithm is not too good, I think somewhat like O(n^2/2) since I check the set of unique items every time to verify if a given item exists. This won't be a big deal if your structure is really that small. But at any rate, this is where a hash-based or a tree-based algorithm would probably be better.
You can also see that I have abstracted away the definition of what is "equal". So you can provide that in a secondary function. Most likely the use of JSON.stringify is a bad idea because it takes time to serialize an object. If you can write your own customized algorithm to compare key by key that'd be probably better.
So, a naive (not recommended) implementation of equals could be somewhat like the proposed in the other answer:
var equals = function(left, right){
return JSON.stringify(left) === JSON.stringify(right);
};
And then you could simply do:
var res = Object.keys(source).reduce(function(res, key){
res[key] = dedup(source[key], equals);
return res;
},{});
Here is my version:
var obj = {} // JSON object provided in the post.
var result = Object.keys(obj);
var test = result.map(function(o){
obj[o] = obj[o].reduce(function(a,c){
if (!a.some(function(item){
return JSON.stringify(item) === JSON.stringify(c); })){
a.push(c);
}
return a;
},[]); return obj[o]; });
console.log(obj);//outputs the expected result
Using Array.prototype.reduce along with Array.prototype.some I searched for all the items being added into the new array generated into Array.prototype.reduce in the var named a by doing:
a.some(function(item){ return JSON.stringify(item) === JSON.stringify(c); })
Array.prototype.some will loop trough this new array and compare the existing items against the new item c using JSON.stringify.
Try this:
var duplicatedDataArray = [];
var DuplicatedArray = [];
//Avoiding Duplicate in Array Datas
var givenData = {givenDataForDuplication : givenArray};
$.each(givenData.givenDataForDuplication, function (index, value) {
if ($.inArray(value.ItemName, duplicatedDataArray) == -1) {
duplicatedDataArray.push(value.ItemName);
DuplicatedArray.push(value);
}
});