Scanning all/specific arrays values when filtering an array of arrays

Question

Here is the sample code:

var myArray = [["one", "two"], ["three", "four"]]

var filteredArray = myArray.filter{ value in value[1] != "four"}

filteredArray //[["one", "two"]]

This code is supposed to filter out any array that contains "four". It does it properly, but only because I target specific array with value[1] because I know it contains "four". How should I reformat this code so I don't need to specify specific array, so it will scan all values in there? When using a "for loop", we have a declared "i" variable we can use. But how to do similar with .filter function ?

Also, even more specific, how could I reformat this code so I can filter array and exclude all that have "four" but specifically as their second value (index [1]) and not if they have "four" in any other index position as in previous requirement. Again in the absence of an "i" variable, I don't see how to do it. Your help is appreciated.

Antonio · Accepted Answer · 2014-11-04 11:48:52Z

1

Knowing that the filter callback receives an inner array at each iteration, we can use reduce on that array to check if it contains the four string:

var filteredArray = myArray.filter {
    let count = $0.reduce(0) {
        $0 + ($1 == "four" ? 1 : 0)
    }

    return count == 0
}

In the reduce closure, if one or more elements is four, the return value will be an integer greater than zero.

answered Nov 4, 2014 at 11:48

Antonio

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Robert Brax Over a year ago

smart it helped me get it tsk

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