So, back to today.
The name of the problem is "Where Art Thou," but this doesn't really tell you anything about the problem, so I'll give a little more details. In this problem, I have to go filter through an object and return certain items, if they are found. Here's a screenshot:
And here's the sample inputs and the code to start off with:
This code allows me to return all the "first" values in collection:
function where(collection, source) {
var arr = [];
for (var j = 0; j < collection.length; j++){
arr.push(collection[j].first);
}
return arr;
}
where([{ first: "Romeo", last: "Montague" }, { first: "Mercutio", last: null }, { first: "Tybalt", last: "Capulet" }], { last: "Capulet" });
The output would be:
Then, if we switch it up and use .last as the key to search for, like so:
function where(collection, source) {
var arr = [];
for (var j = 0; j < collection.length; j++){
arr.push(collection[j].last);
}
return arr;
}
where([{ first: "Romeo", last: "Montague" }, { first: "Mercutio", last: null }, { first: "Tybalt", last: "Capulet" }], { last: "Capulet" });
Then is that case, the output would be:
That's neat.
So, what I've learned from doing these algorithms is that the first thing I need to do is to actually understand the problem. So let's do that, let's clarify what exactly we're being asked to do.
Okay, I understand the problem now. Every key and value pair that is present in the second parameter (an object) has to be present in an object in the first parameter (an array of objects) in order for us to return the object in the first parameter. If there are extra key and value pairs present in the object in the array that is a match, those should be returned as well.
I'm going over this code:
for (var key in obj) {
if (Object.prototype.hasOwnProperty.call(obj, key)) {
var val = obj[key];
// use val
}
}And this code:
for(var key in objects) {
var value = objects[key];
}They both deal with getting the values of an object. Then this:
function where(collection, source) {
var arr = [];
for (keys in collection) {
arr.push(Object.keys(collection[keys]));
}
return arr;
}
Returns all the key and value pairs in the collection array:
I'm learning, I'm still pretty new at working with objects, I've done a lot of challenges with arrays, but objects are still new to me. Hmmmm, I've got this so far...
function where(collection, source) {
var arrS = [];
var arrC = [];
for(var key in source) {
arrS.push(key + ": " + source[key]);
}
for (var i = 0; i < collection.length; i++) {
for(var key2 in collection[i]) {
arrC.push(key2 + ": " + collection[i][key2]);
}
}
return arrC;
}
where([{ first: "Romeo", last: "Montague" }, { first: "Mercutio", last: null }, { first: "Tybalt", last: "Capulet" }], { first: "Tybalt", last: "Capulet" });
The Output is:
What it does is it puts both arrays into another array...which I can then access to compare? But they're strings now, not objects...
Yeah, that won't do me any good. But hey, I'm getting a lot of practice with manipulating objects.
Okay, I've reset the code, starting from scratch again.
Oh no! I realized I've been making a big mistake! The input for source should actually just be:
{ last: "Capulet" }
I had added a first name to that input a while back to test something, and then I forgot to remove it, and this has been affecting everything. Well, at least now that I reset it, I can begin correctly again.
Okay, I'm going to save some code, I put source inside an array, and that allows me to manipulate it a little better:
function where(collection, source) {
var sourceArray = [];
sourceArray[0] = source;
var array2 = [];
var array3 = [];
var collectionArray = collection;
// What's in a name?
for (var keys in collection) {
array2.push(collection[keys]);
}
//return array2;
for (var keys2 in sourceArray) {
array3.push(sourceArray[keys2]);
}
return array3;
}
where([{ first: "Romeo", last: "Montague" }, { first: "Mercutio", last: null }, { first: "Tybalt", last: "Capulet" }], { last: "Capulet" });
But I'm still figuring things out...well, I managed to get it to solve the problem for the first scenario:
function where(collection, source) {
var sourceArray = [];
sourceArray[0] = source;
var arrayCol = [];
var arraySour = [];
var collectionArray = collection;
// What's in a name?
for (var keys in collection) {
arrayCol.push(collection[keys]);
}
//return array2;
for (var keys2 in sourceArray) {
arraySour.push(sourceArray[keys2]);
}
//return arraySour;
for (var i = 0; i < arrayCol.length; i++) {
if( arrayCol[i].hasOwnProperty('last') && arrayCol[i].last === arraySour[0].last) {
var jack = [];
jack.push(arrayCol[i]);
return jack;
}
}
}
where([{ first: "Romeo", last: "Montague" }, { first: "Mercutio", last: null }, { first: "Tybalt", last: "Capulet" }], { last: "Capulet" });
Now I need to make it so that a variable holds the "last" value and changes as the inputs change. This problem's a challenge.
I got this one to work also:
function where(collection, source) {
var sourceArray = [];
sourceArray[0] = source;
var arrayCol = [];
var arraySour = [];
var collectionArray = collection;
// What's in a name?
for (var keys in collection) {
arrayCol.push(collection[keys]);
}
//return array2;
for (var keys2 in sourceArray) {
arraySour.push(sourceArray[keys2]);
}
//return arraySour;
for (var i = 0; i < arrayCol.length; i++) {
if( arrayCol[i].hasOwnProperty('a') && arrayCol[i].a === arraySour[0].a) {
var jack = [];
jack.push(arrayCol[i]);
}
}
return jack;
}
where([{ "a": 1, "b": 2 }, { "a": 1 }, { "a": 1, "b": 2, "c": 2 }], { "a": 1, "c": 2 });
The output is:
I may be on the right track...
Hmmm...now I got the 2nd one working...
This is neat...this code works for the first and the second parameters, as long as I change 'last' to 'a', which is the key used in the first and second parameter, respectively. So I need to grab the name of the key from source, then place that in a variable, then use that variable in the formula. The reason the other two don't work (I think) is because they have a second key and value pair in source, and I haven't configured my code to run more than one time, as far as source is concerned. I'll work on that problem after the variable issue is solved, working on that now.
Okay, I've got two of the scenarios to work, here's a pic:
And I'm saving the code:
function where(collection, source) {
var sourceArray = [];
sourceArray[0] = source;
var arrayCol = [];
var arraySour = [];
var collectionArray = collection;
var skn = Object.keys(source);
// What's in a name?
for (var keys in collection) {
arrayCol.push(collection[keys]);
}
//return array2;
for (var keys2 in sourceArray) {
arraySour.push(sourceArray[keys2]);
}
//return arraySour;
var jack = [];
for (var i = 0; i < arrayCol.length; i++) {
if( arrayCol[i].hasOwnProperty(skn) && arrayCol[i][skn] === arraySour[0][skn]) {
jack.push(arrayCol[i]);
}
}
return jack;
}
where([{ first: "Romeo", last: "Montague" }, { first: "Mercutio", last: null }, { first: "Tybalt", last: "Capulet" }], { last: "Capulet" });
Now I need to get the other two to work. The other two will work if I get the formula to cycle again with extra keys...that's what I need to work on next.
I solved it! Holy Toledo!!!
Neat! Here's the code, so I can go over it anytime:
function where(collection, source) {
var sourceArray = [];
sourceArray[0] = source;
var arrayCol = [];
var arraySour = [];
var collectionArray = collection;
var skn = Object.keys(source);
for (var keys in collection) {
arrayCol.push(collection[keys]);
}
for (var keys2 in sourceArray) {
arraySour.push(sourceArray[keys2]);
}
var jack = [];
for (var i = 0; i < arrayCol.length; i++) {
if( arrayCol[i].hasOwnProperty(skn) && arrayCol[i][skn] === arraySour[0][skn]) {
jack.push(arrayCol[i]);
}
}
if (skn.length > 0) {
for (var j = 0; j < arrayCol.length; j++) {
if( arrayCol[j].hasOwnProperty(skn[1]) && arrayCol[j][skn[1]] === arraySour[0][skn[1]]) {
jack.push(arrayCol[j]);
}
}
}
return jack;
}
where([{ "a": 1, "b": 2 }, { "a": 1 }, { "a": 1, "b": 2, "c": 2 }], { "a": 1, "b": 2 });
This was the input on that one:
I'm going to take an hour or so to go over everything I just did, I really want to get the concepts here. Nonetheless, 15 more Intermediate JavaScript Algorithms to go!
I'll note that my solution looks nothing at all like the other solutions on this problem, they use .filter(), .forEach(), .reduce(), and .every(). I need to learn how to use those methods.
Well, I put in an extra hour and solved the next one already!
Here's the problem:
And here's a pic with my solution:
That one was much, much, much easier. That's my first draft, I'll see if I can clean it up a little, I just solved it a few seconds ago. Woohoo!
14 more Intermediate JavaScript Algorithms left!
SUMMARY OF CODING SKILLS
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Note: I switched to FCC for the great online community and better updates/support.
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