Q: I wrote the code below but it does not work for last challenge. I cant figure out how and what to pass in to the toPigLatin function. I would really appreciate it if someone could look at code below and figure out what I am doing Wrong. $paragraphs = $("p"); for (var i = 0;i < $paragraphs.length;i++) { var element = $paragraphs[i]; var $paragraph = $(element); var $done = toPigLatin $("$paragraph.text"); $paragraph.text($done.); }

Instead of doing: ``` var element = $paragraphs[i]; var $paragraph = $(element); ``` Just use `var element = $($paragraphs[i]);`. It's better because you're using less variables, and that's better than using unnecessary variables. Also, you forgot to use the `var` keyword with `$paragraphs = $("p");`, so JavaScript won't know what to do with it. Also, `var $done = toPigLatin $("$paragraph.text");` would cause an error because you're putting a `$` in between the function `toPigLatin` and the parentheses, so the JavaScript (remember, jQuery is used with JavaScript) can't run the function. Second of all, you put `$paragraph.text` inside quotes, so JavaScript would just treat it as a string, and not run it as code. Last of all, `$paragraph.text($done.);` has one problem, you put `$done.` inside the parentheses, so JavaScript will think that you're trying to find a values within the Object (in this case: `$done.`), but you didn't put anything after the dot, so JavaScript won't know what to do, also, you're not even wanting to call from an Object here, well here's the code for the challenge: ``` var $paragraphs = $("p"); for(var i = 0;i < $paragraphs.length;i++) { var element = $($paragraphs[i]); element.text(toPigLatin(element.text())); } ``` Good luck and happy coding!

Q: The fact that you use TWO diff variables "paragraphs" PLURAL and then " paragraph" SINGLE tripped me up. SO i don't get how the single one knows anything about the plural one?

The plural contains the collection or array, the singular contains the current array item

Q: I noticed that in the Looping through jQuery collections video (around 3:46), Pamela used several lines of code to loop: `var $paragraphs = $("p"); $paragraphs.each(function(index, element) { var $paragraph = $(element); $paragraph.html( $paragraph.html() + "..wowee!"); });` But in this review page, we're shown that we can use a bit of shorthand: `$("p").each(function() { $(this).text( $(this).text() + "..wowee!"); });` (Please correct my code if I made a mistake somewhere!) Anyway, my question was: is it better to use more code or less, or does it depend? I can see that it would be much more efficient to use less code, but more self-commenting and human-friendly to use more. And another benefit of naming variables might be to access them more easily if the code is more complex. What are other considerations coders might have?

You've pretty much summed it up. The only thing I might add is that if you use variables, you can reuse them if necessary.

Q: for Loopy language, I did: var $paragraphs = $("p"); $paragraphs.each(toPigLatin); I received a runtime error that str.replace (from the toPigLatin function) was not a function.

`.each()` iterates through a jQuery collection. You must pass it a callback function that is written to operate on the context of a DOM node. `toPigLatin` in it of itself does not modify text of a DOM node, so using it as your callback function does not help you achieve what you want.

Q: How does the toPigLatin function from the last challenge work? var toPigLatin = function(str) { if (!str.replace) { return 'ERROR: Expected a string!'; } return str.replace(/\b(\w)(\w+)\b/g, '$2-$1ay').toLowerCase();

The first three lines of the function is an `if` statement. It checks if `str.replace` is not existent. Every value can be converted into a Boolean, simply with this logic: if the value is one of (undefined, null, "", NaN, false, 0), then the value is `false` as a Boolean. If it is not one of those values, then it is `true` as a Boolean. A string value has a `replace()` method, and a function is not one of those Boolean-falsify values. So, it would return true. But, there's a `!` there, which returns the opposite. The opposite of true (str.replace) is false. If str.replace is oneof the fake values, then it will escape the function with `return`. Besides giving back a value, `return` can escape the function. The last line calls `str.replace()`, and passes it a regular expression. Regular expressions are used to perform complex search patterns.

Question 1

I don't understand what to do for loopy language??

Accepted Answer

You want to loop through the p tags (not the individual words) and apply toPigLatin() on them. How you do that is you first loop through the p tags like this:

        var $paragraphs = $("p");
        $paragraphs.each(function(index,element){
           
        });

Then you need to make each element into a jquery collection object
var $paragraph = $(element);
Then call toPigLatin on each paragraph like this:

        var $paragraphs = $("p");//find all the <p> tags
        $paragraphs.each(function(index,element){//iterates through each paragraph
            var $paragraph = $(element);//turns it into a jquery collection object so .text() will work
            $paragraph.text( toPigLatin($paragraph.text()) );//change the text to pig latin
        });

tags $paragraphs.each(function(index,element){//iterates through each paragraph var $paragraph = $(element);//turns it into a jquery collection object so .text() will work $paragraph.text( toPigLatin($paragraph.text()) );//change the text to pig latin }); ```

Question 2

For looping through collections, is it necessary to include (index, element) or is that just illustrating the parameters that will get called anyway and you can you just put ()?

Accepted Answer

You can just use `function ()` and refer to the current element with `this`. You'd really only need the parameters if you needed to know the index too, and then you'd really only need the first one.

If a function in JS is defined with parameters and not called with parameters, or called with parameters and not defined with paramaters, they're `undefined` in the first case or just thrown away in the second case.

Since `this` gets bound by jQuery, you can just not use or declare the paramaters.

Question 3

I wrote the code below but it does not work for last challenge. I cant figure out how and what to pass in to the toPigLatin function. I would really appreciate it if someone could look at code below and figure out what I am doing Wrong.

$paragraphs = $("p");
for (var i = 0;i < $paragraphs.length;i++) {
    var element = $paragraphs[i];
    var $paragraph = $(element);
    var $done = toPigLatin $("$paragraph.text");
    $paragraph.text($done.);

}

Accepted Answer

Instead of doing:
```
var element = $paragraphs[i];
var $paragraph = $(element);
```
Just use  `var element = $($paragraphs[i]);`. It's better because you're using less variables, and that's better than using unnecessary variables. Also, you forgot to use the `var` keyword with `$paragraphs = $("p");`, so JavaScript won't know what to do with it.

Also, `var $done = toPigLatin $("$paragraph.text");` would cause an error because you're putting a `$` in between the function `toPigLatin` and the parentheses, so the JavaScript (remember, jQuery is used with JavaScript) can't run the function. Second of all, you put `$paragraph.text` inside quotes, so JavaScript would just treat it as a string, and not run it as code.

Last of all, `$paragraph.text($done.);` has one problem, you put `$done.` inside the parentheses, so JavaScript will think that you're trying to find a values within the Object (in this case: `$done.`), but you didn't put anything after the dot, so JavaScript won't know what to do, also, you're not even wanting to call from an Object here, well here's the code for the challenge:

```
var $paragraphs = $("p");
for(var i = 0;i < $paragraphs.length;i++) {
    var element = $($paragraphs[i]);
    element.text(toPigLatin(element.text()));
}
```

Good luck and happy coding!

Question 4

The fact that you use TWO diff variables "paragraphs" PLURAL and then " paragraph" SINGLE tripped me up.   SO i don't get how the single one knows anything about the plural one?

Accepted Answer

The plural contains the collection or array, the singular contains the current array item

Question 5

I noticed that in the Looping through jQuery collections video (around 3:46), Pamela used several lines of code to loop:
 
`var $paragraphs = $("p");
$paragraphs.each(function(index, element) {
            var $paragraph = $(element);
            $paragraph.html( $paragraph.html() + "..wowee!");
});`

But in this review page, we're shown that we can use a bit of shorthand:

`$("p").each(function() {
            $(this).text( $(this).text() + "..wowee!");
});`

(Please correct my code if I made a mistake somewhere!)

Anyway, my question was: is it better to use more code or less, or does it depend? I can see that it would be much more efficient to use less code, but more self-commenting and human-friendly to use more. And another benefit of naming variables might be to access them more easily if the code is more complex. What are other considerations coders might have?

Accepted Answer

You've pretty much summed it up.
The only thing I might add is that if you use variables, you can reuse them if necessary.

Question 6

for Loopy language,  I did:
var $paragraphs = $("p");
    $paragraphs.each(toPigLatin);
I received a runtime error that str.replace (from the toPigLatin function) was not a function.

Accepted Answer

`.each()` iterates through a jQuery collection. You must pass it a callback function that is written to operate on the context of a DOM node. `toPigLatin` in it of itself does not modify text of a DOM node, so using it as your callback function does not help you achieve what you want.

Question 7

How does the toPigLatin function from the last challenge work?

var toPigLatin = function(str) {
    if (!str.replace) {
        return 'ERROR: Expected a string!';
    }
    return str.replace(/\b(\w)(\w+)\b/g, '$2-$1ay').toLowerCase();

Accepted Answer

The first three lines of the function is an `if` statement. It checks if `str.replace` is not existent. Every value can be converted into a Boolean, simply with this logic: if the value is one of (undefined, null, "", NaN, false, 0), then the value is `false` as a Boolean. If it is not one of those values, then it is `true` as a Boolean.

A string value has a `replace()` method, and a function is not one of those Boolean-falsify values. So, it would return true. But, there's a `!` there, which returns the opposite.
The opposite of true (str.replace) is false.

If str.replace is oneof the fake values, then it will escape the function with `return`. Besides giving back a value, `return` can escape the function.

The last line calls `str.replace()`, and passes it a regular expression. Regular expressions are used to perform complex search patterns.

Course: Computer programming - JavaScript and the web > Unit 7

Review: jQuery collections & looping

jQuery collections

Looping through collections

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