KOTLIN Find Match Between 2 Lists-CodePudding

So basically I've 2 lists:

val list = context.packageManager.getInstalledPackages(0);
var listOfAvs: MutableList<String> = arrayListOf(
            "com.app1",
            "com.app2"
)

I want to find common elements between the 2 lists. To make both same kind of list I wrote this code

val listMuted: MutableList<String> = arrayListOf()
        var counter = 0
        for(apks in list)
        {
            listMuted.add(apks.packageName.toString())
}

I can't really figure out how to match common elements between both lists. I'm not here writing the code as I made like tens of different functions trying to do that but all of them failed. Please help I'm since a month trying to achieve it

CodePudding user response：

There is an intersect function that makes this really easy. You can use map to pull the Strings out of the list of PackageInfo.

val commonItems: Set<String> = list
    .map { it.packageName }
    .intersect(listOfAvs)

If you need them in a list you can call toList() or toMutableList() on this result.

CodePudding user response：

I add some comment between the codes. If you have any question, please comment.

        // Well we have to compare with the packagename, so I changed the list to packageName list
        val list: List<String> =
            application.packageManager.getInstalledPackages(0).map { it.packageName.toString() }
        // There wasn't any change at the listOfAvs list and listMuted list.
        val listOfAvs: MutableList<String> = arrayListOf(
            "com.app1",
            "com.app2"
        )
        val listMuted: MutableList<String> = arrayListOf()
        // With each apk
        for (apkPackageName in list) {
            // if there is the same package name at the listOfAvs list
            if (apkPackageName in listOfAvs) {
                // Add the apk to the listMuted list
                listMuted.add(apkPackageName)
            }
        }