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    Add and Remove Items in Arrays using Filter, Reject and Partition in Ramda
    2m 9s

Add and Remove Items in Arrays using Filter, Reject and Partition in Ramda

Andy Van Slaars
InstructorAndy Van Slaars

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We'll learn how to get a subset of an array by specifying items to include with filter, or items to exclude using reject. We'll also look at how to get the results from both filter and reject, neatly separated with partition.

Mike
Mike
~ 4 years ago

Nicely done. What tools did you use to record this?

Andy Van Slaars
Andy Van Slaarsinstructor
~ 4 years ago

Mike, thanks for watching!

I'm using Atom with the Atom Material UI and syntax themes. The terminal is the term3 plugin for Atom, though I use iTerm for my terminal the majority of the time. I record the screen and do my editing with Screenflow and the audio is recorded with a supercardoid mic connected through a USB audio interface.

David
David
~ 3 years ago

How could I extend this to filter global search style 1 character at a time to filter a nested array? The outer array are the parent rows displayed and the nested array is the expanded rows displayed under each parent. Is it possible to filter such an array?

pablo
pablo
~ 2 years ago

I love the functional programming and this library in particular, don't misunderstand my comment.

Is there any extra benefit in using ramda's filter method instead of the original JavaScript? I ask this, to clarify concepts, I understand that within the benefits offered by the filter of ramda, is to iterate objects and take advantage of the currificacion or partial application. But in this case you don't use either of those two benefits. If that is the case, don't you think it would be worthwhile to comment on the detail of when it's convenient to use a functional approach with this library and when to use original API from the language?

If I'm wrong and the method has other benefits please let me know.

Robert Pearce
Robert Pearce
~ 2 years ago

@pablo: The benefit is that now you can compose a specific filter operation and reuse it over and over with different data and even do so in a point-free way. I wrote an article on Ramda Chops: Map, Filter & Reduce, and this should help explain in detail. But for now:

const dogCheck = pet => pet.type === 'dog'
const getName = prop('name')
const onlyDogs = filter(dogCheck)
const getDogsNames = compose(map(prop('name')), onlyDogs)

getDogsNames([ /* one set of data */ ]) // some results
getDogsNames([ /* another set of data */ ]) // some different results