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example 1
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hey again everybody it's me big surprise
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there today I'm going to explain the
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filter method in JavaScript the filter
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method creates a new array by filtering
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out elements in this example we'll
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create an array of
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numbers we will filter out any numbers
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that are odd let's add the numbers 1
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through
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7 now we need a
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function
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function is even we have one parameter
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we have an element that's going to be
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provided to us by the filter method we
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are going to return then write a
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condition we will take our element
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modulus 2 the modulus operator gives you
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the remainder of any division you can
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use modulus 2 to check to see if a
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number is even if this condition is zero
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strictly equal to zero then we will
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return true we will be returning a
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Boolean true or false the filter method
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will will take any values that return
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true and stick them within a new array
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which will effectively filter out any
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elements we don't need that don't return
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true let's see if this works I will
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create a new array even nums equals take
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our original array use the filter method
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pass in a call back is even we will
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display
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console.log our new array even numbers
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and there we are
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2 4 6 let's do this with odd
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numbers function is
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odd take our element modulus 2 is this
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strictly not equal to zero that means
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the number is
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odd let's create a new array let odd
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nums equals our original array numbers
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do use the filter method passing a call
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back is odd let's check out our new
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array odd
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nums there we are we have the numbers 1
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35 7 any numbers that are odd let's go
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over another
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example I will create an array of Ages
example 2
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I'll use const this time instead of let
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const ages Pretend We're teaching a
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college class we might have some
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students still in high school let's say
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a student is 16 another is 17 two are 18
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19 20 and then we have somebody that's
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just a little bit older they're um 60
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we'll use the filter method to filter
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out anybody that is under 18 we will
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find all of the adults we will need a
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function function is adult we have one
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element as a parameter that's going to
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be provided to us we will return a
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condition return check our element is it
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great greater than or equal to
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18 so that's our function let's create a
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new array of adults equals take our
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original array dot use the filter method
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pass in a call back is adult then
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display our new array
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console.log
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adults we have five elements the age of
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the students is 18 18 19 20 and 60 let's
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do this with is children to find anybody
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that's under
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18 is child
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function return element less than 18
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we'll create a new array const children
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equals take our original array use the
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filter method pass in a call back is
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child then display the new array we have
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two students that are children one is 16
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the other is 17 last example we'll
example 3
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create an array of words const
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words add some words I think I'll add
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some fruit I'll add an
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apple
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orange
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banana
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kiwi
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pomegranate and a
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coconut I will filter out any words
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where the length of that word is above
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six so we will create a function
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function get short
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words we have an element as a
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parameter we will return a condition we
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will check if our element access the
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length property of that element they're
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strings so they all have a length
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property how many characters are they
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long that's the length check to see if
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the length of this element is less than
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or equal to
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six if it is return true if not return
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false we will create a new array let's
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call this array short words equals take
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our array use the built-in filter method
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pass in a call back get short words then
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we will console.log the new array short
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words in our array there are four
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elements with the length of the
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characters of each string is six
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surrender Apple orange banana kiwi then
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to finish this off let's get any long
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words we'll create a new
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function get long words check the length
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of the element to see if it's above six
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then we will create a new array const
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long words equals take our original
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array use the filter method pass in a
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call back get long words then we will
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display our new array long words within
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our original array there's two words
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that are considered long pomegranate and
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coconut these words each have more than
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six characters coconut is seven
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pomegranate is 11 all right everybody
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that is the filter method it creates a
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new array by filtering out elements your
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callback is likely going to check in
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condition does each element pass this
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condition and well everybody that is the
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filter method in
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JavaScript