In Protractor, there is the .first() and .last() methods available on ElementArrayFinder:
var elements = element.all(by.css(".myclass"));
elements.last();
elements.first();
But, how to get the element just before the last one (penultimate) without knowing how many elements are there in total?
You can use negative indexing to get the elements from the end by index:
Negative indices are wrapped (i.e. -i means ith element from last)
elements.get(-2); // the element before last
Related
Suppose I have an Javascript array,
var example = [and, there,sharma<br, />, ok, grt]
Now I want to randomly delete some array values - but not those values which have
<br
in them, in the above example, I want to make sure
"sharma<br" is not deleted.
I also do not want to delete "/>".
Can anyone help me. I would really appreciate the answer.
First of all, that is not a valid array, unless you are missing the string quotes. Anyway, what you are searching for is Array.Filter. In your case :
var filtered = example.filter(v => v.indexOf("<br") != -1 || v.indexOf("/>") != -1)
If I have understood the problem correctly, then you want to keep those entries in the array which have substrings "<br" and "/>"
If thats the case, you can try using javascript string method includes() to see if a string contains a particular substring.
JavaScript array must be created as below
var example = ["and"," there"",sharma<br","/>","ok"," grt"];
Using splice method , to delete the array values specifying the index positions.
array splice() method changes the content of an array, adding new elements while removing old elements.
Syntax
Its syntax is as follows −
array.splice(index, howMany, [element1][, ..., elementN]);
Parameter Details
index −
Index at which to start changing the array.
howMany −
An integer indicating the number of old array elements to remove. If howMany is 0, no elements are removed.
element1, ..., elementN −
The elements to add to the array. If you don't specify any elements, splice simply removes the elements from the array.
Return Value
Returns the extracted array based on the passed parameters.
var removed = arr.splice(2, 2);
This would remove your suggested output to be my assumption .
I want to atomically remove the first n elements of an array field.
Right now, I use model.find(), then doc.arrayField.slice(n), then doc.save(). But this loads the entire document in memory (bad if document is very large), and it would kill the atomicity.
Is there a way to achieve this atomically in MongoDB/Mongoose?
Thanks!
You can use $pop to remove first element atomically. Or if you can specify which fields to remove you can use $pull to remove multiple items from an array. Otherwise you cannot remove first n elements from array in an atomic operation using mongodb.
db.yourCollection.update({}, {$pop: {arrayField: 1}}}) // will remove the first element from arrayField
db.yourCollection.update({}, {$pull: {arrayField: {foo: "bar"}}}}) // will remove all elements whose foo field equal to bar from arrayField.
MongoDB provides $slice operator for array updates. https://docs.mongodb.org/v3.0/reference/operator/update/slice/
You can use in Mongoose updateClause too.
Instead of loading all arrayField data in memory, you can use $slice to project docs with first n elements of arrayFields like this
model.find({}, {arrayField : {$slice: n}}) // n is first n elements
Now you can remove those n elements using
doc.arrayField.slice(n);
doc.save();
I have a jQuery object that is created via jQuery .find() as seen below...
var $mytable= $('#mytable');
var $myObject = $mytable.find("tbody tr");
This works great and creates a jQuery object of all the tr elements in the tbody. However, as I'm looping over the data, I need to be able to remove parts of the object as I go. For instance, if the above call returns a jQuery object named $myObject with a length of 10, and I want to remove the index 10, I thought I could just do $myObject.splice(10,1) and it would remove the element at index 10. However this doesn't seem to be working.
Any ideas why? Thank you!
UPDATE
I basically just want to be able to remove any element I want from $myObject as I loop through the data. I know it's zero based (bad example above I guess), was just trying to get my point across.
UPDATE
Okay, so I create the object using the find method on the table and at it's creation it's length is 24. As I loop over the object, when I hit an element I don't want I tried to use Array.prototype.splice.call($rows,x,1) where x represents the index to remove. Afterwards when I view the object in the console, it still has a length of 24.
Use .not() to remove a single element, then loop through the jQuery object at your leisure:
var $myObject = $mytable.find('tbody tr').not(':eq(9)'); // zero-based
http://jsfiddle.net/mblase75/tLP87/
http://api.jquery.com/not/
Or if you might be removing more than one:
var $myObject = $mytable.find("tbody tr:lt(9)");
http://jsfiddle.net/mblase75/9evT8/
http://api.jquery.com/lt-selector/
splice is not part of the jQuery API, but you can apply native Array methods on jQuery collections by applying the prototype:
Array.prototype.splice.call($myObject, 9, 1); // 0-index
You can also use pop to remove the last item:
Array.prototype.pop.call($myObject);
This should also give you a correct length property.
splice is an array method, not a jQuery object method.
Try slice
Javascript uses zero-based arrays. This means that the final item in the array (i.e. the 10th item) will be at index 9.
$myObject[9]
So you need something like this:
$myObject.splice(9, 1);
This will remove the element from your existing array, and also return it.
You could also use filter :
var $myObject = $mytable.find("tbody tr").filter(':lt(9)');
You can use .remove to remove an element from the DOM.
So to remove the element at index 9 of the $myObject array, use:
$myObject.eq(9).remove();
If you want to keep the element that you are removing, you can also do:
var removedElement = $myObject.eq(9);
removedElement.detach();
rowData = [];
alert(rowData[0]);
gives me [Ti.UI.TableViewRow]
Now how can i remove this element... i have been using rowData.splice(), but i have no idea on what to pass to remove it.
Thanks
try rowData.splice(0, 1); the first argument indicates the index of item to be removed, the second indicates how many items should be removed
In the code you present rowData should be empty, so rowData[0] should be undefined. I suppose something is pushed to rowData in between? Anyway, there are several ways to remove elements from arrays:
You can remove all elements at once
from an array using rowData.length =
0.
If you want to remove 1 element, use
the Array.splice method. E.g.
removing the first element:
rowData.splice(0,1) (means remove
1 element of rowData starting from
element 0 (the first element).
If it's only the first element you
want to remove you could also use the
shift method: rowData.shift().
The last method you can use is
slice: rowData = rowData.slice(1)
(means: give me all elements from
rowData starting at the first element and
assign the result to rowData),
or rowData.slice(1,4) (means:
give me all elements from
rowData starting at the first element,
ending at the fourth element, and
assign the result to rowData).
If you want to remove the element(s) entirely, splice() will return a new array with the member(s) removed.
You can also use the delete operator, but this won't affect the Array size and the member will be undefined. This is will also make it non enumerable.
This is my code:
function insert(){
var loc_array = document.location.href.split('/');
var linkElement = document.getElementById("waBackButton");
var linkElementLink = document.getElementById("waBackButtonlnk");
linkElement.innerHTML=loc_array[loc_array.length-2];
linkElementLink.href = loc_array[loc_array.length];
}
I want linkElementLink.href to grab everything but the last item in the array. Right now it is broken, and the item before it gets the second-to-last item.
I’m not quite sure what you’re trying to do. But you can use slice to slice the array:
loc_array = loc_array.slice(0, -1);
Use pathname in preference to href to retrieve only the path part of the link. Otherwise you'll get unexpected results if there is a ?query or #fragment suffix, or the path is / (no parent).
linkElementLink.href= location.pathname.split('/').slice(0, -1).join('/');
(But then, surely you could just say:)
linkElementLink.href= '.';
Don't do this:
linkElement.innerHTML=loc_array[loc_array.length-2];
Setting HTML from an arbitrary string is dangerous. If the URL you took this text from contains characters that are special in HTML, like < and &, users could inject markup. If you could get <script> in the URL (which you shouldn't be able to as it's invalid, but some browser might let you anyway) you'd have cross-site-scripting security holes.
To set the text of an element, instead of HTML, either use document.createTextNode('string') and append it to the element, or branch code to use innerText (IE) or textContent (other modern browsers).
If using lodash one could employ _.initial(array):
_.initial(array): Gets all but the last element of array.
Example:
_.initial([1, 2, 3]);
// → [1, 2]
Depending on whether or not you are ever going to reuse the array you could simply use the pop() method one time to remove the last element.
linkElementLink.href = loc_array[loc_array.length]; adds a new empty slot in the array because arrays run from 0 to array.length-1; So you returning an empty slot.
linkElement.innerHTML=loc_array[loc_array.length-2]; if you use the brackets you are only getting the contents of one index. I'm not sure if that is what you want? The next section tells how to get more than one index.
To get what you want you need for the .href you need to slice the array.
linkElementLink.href = loc_array.slice(0,loc_array.length-1);
or using a negative to count from the end
linkElementLink.href = loc_array.slice(0,-1);
and this is the faster way.
Also note that when getting to stuff straight from the array you will get the same as the .toString() method, which is item1, item2, item3. If you don't want the commas you need to use .join(). Like array.join('-') would return item1-item2-item3. Here is a list of all the array methods http://www.w3schools.com/jsref/jsref_obj_array.asp. It is a good resource for doing this.
.slice(number you want)
if you just want the first 4 elements in an array its array.slice(3)
doing a negative number starts from the end of the array