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uh hello guys welcome to this video so
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in this video we'll be looking at two
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methods two array methods which is flat
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and flat map so we'll be looking at
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these two methods so flat method is
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specifically used to actually flatten
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out an array with the depth levels so
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let me show you an example right here so
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let me take an example of an array which
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has some values 1 3 4
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and we also have a nested array as well
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so this is a nested
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array this is actually the array that is
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shown so we have this is actual outer
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array that you
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see this is the inner array the nested
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array that you
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see so now if you want to flatten this
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array
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into the same level if you want to just
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split this nested
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array so the output will be
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135 and 356 78 so if you want to split
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this up we use the flat method flatten
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method so for doing this we can create a
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new array we can
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create
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flat and then we can simply call this
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method flat and here we need to Simply
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pass the argument the actual array that
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you want to flatten you are simply
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passing it to this
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function so if you just console log it
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it actually flattens out the array and
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if I console log it you will see all
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this
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array oh sorry we don't need to pass it
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we are directly calling this if you see
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we calling this on this array we don't
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need to pass anything right here so by
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default it takes the depth level so if
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you don't pass anything it actually
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takes this so if you you you can also
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write like this but if you don't pass
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any argument it takes one value as
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default and now if you see it will flat
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out the
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array you will actually see the output
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like this 13 5 35 678 so if you see this
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it actually splitted up this nested
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array it basically remove this
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bracket and this is actually your output
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135 356
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78
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so now we can even have nested array
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inside this we can even have another
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nested array
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so we can
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say so we can even do like this as as
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well so if you see we have this outer
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array this was our outer array this is
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actually a nested
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array inside this also we have another
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nested array so you can see the depth
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level is now two so depth level is now
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two so if you
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now execute the same method it will give
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you this result it will not flatten out
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this array this is
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the this this is actually the array it
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will only flatten out by one by default
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if you don't pass anything in this
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function it actually takes the value one
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the default depth level so here need to
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specifically pass the depth level that
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you want to flatten on this array if you
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now pass two it will first of all
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flatten this
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array and then it will also flatten this
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array as well removing this now the
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output will be 135 356 4578 so if you
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closely look we have got this output
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eight elements in this array and
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everything has been flattened out so
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this is actually the method guys flat
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method which is used here we can provide
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the depth level as well if you want to
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flatten this array and now we'll be
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looking at the method flat map flat map
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is specifically
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used if you see we have two methods one
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is map and the second one is flat so
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when you combine both these methods
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together we get this method which is
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flat
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map so how we use this method basically
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first of all if you want to map a method
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let's suppose I
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create result and now I need to map this
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so you use first of all the map method I
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will use so let me show you what this
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method does it actually takes all the
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arguments let me modify
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this 1 2 3 4 5 so we actually take
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individual element in this map function
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we pass it in the num and we create a
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new array so we basically multiply this
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num by
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two this is actually the logic we are
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creating a new array using this map
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function
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providing 1 comma then 1 * by 2 1 comma
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2 so it will give you this result if I
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console log
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it it will give you a flatten array if
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you now see this array will not be
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flattened because the flat method hasn't
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been applied so you will actually see
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this nested array 1 comma 2 1 comma 4 1A
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6 1A 8 1A 10 so if you do need to
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flatten this array as well with a single
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step we then combine this using flat map
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so what this function will become it
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will become flat map so you write like
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this so now it will give you this flat
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method 1 2 1 4 1 16 1 18 110 exactly it
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contain 10 elements so all the elements
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have been flattened out in a single step
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using this flat map function if you only
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use the map function it will not flatten
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out your array that's why we use flat
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map function which combines the both the
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functionalities of the flat function and
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also it gives you the functionality of
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the map function as well so this is a
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difference between the two the flat and
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the flat map if you also want to map the
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elements you
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combine that with flat map so these are
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widely used array methods I personally
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use them a lot inside applications this
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is the actual thing how we use it so
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thank you very much for watching this
7:12
video do check out my website as well
7:14
free mediat tools.com which contains
7:17
open-source video tools regarding audio
7:20
video and image and I will be seeing you
7:23
in the next video
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