forked from kimriri/kotlin_study
-
Notifications
You must be signed in to change notification settings - Fork 0
/
PlusMinus.kt
72 lines (60 loc) · 2.27 KB
/
PlusMinus.kt
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
// ref : https://kotlinlang.org/docs/collection-plus-minus.html
fun main() {
}
fun plusMinus() {
val numbers = listOf("one", "two", "three", "four")
val plusList = numbers + "five"
val minusList = numbers - listOf("three", "four")
println(plusList)
println(minusList)
}
fun augmentedAssignment() {
val valNumberCollection = listOf("one", "two", "three", "four")
// Compile error
// valNumberCollection += "five"
// valNumberCollection -= listOf("three", "four")
// valNumberCollection -= "four"
// mutableList로 바꿀 것을 권장, + / - operator 자체가 재할당 하는 형식이기 때문
var varNumberCollection = listOf("one", "two", "three", "four")
varNumberCollection += "five"
varNumberCollection -= listOf("three", "four")
varNumberCollection -= "four"
val valNumberMutableCollection = mutableListOf("one", "two", "three", "four")
valNumberMutableCollection += "five"
valNumberMutableCollection -= listOf("three", "four")
valNumberMutableCollection -= "four"
}
// region ref : https://kotlinlang.org/docs/collection-write.html#removing-elements
fun sampleCodeForAddingElements() {
val numbers = mutableListOf(1, 2, 3, 4)
numbers.add(5)
println(numbers)
val numbersAddAll = mutableListOf(1, 2, 5, 6)
numbersAddAll.addAll(arrayOf(7, 8))
println(numbersAddAll)
numbersAddAll.addAll(2, setOf(3, 4))
println(numbersAddAll)
val numbersPlusOperator = mutableListOf("one", "two")
numbersPlusOperator += "three"
println(numbersPlusOperator)
numbersPlusOperator += listOf("four", "five")
println(numbersPlusOperator)
}
fun sampleCodeForRemovingElements() {
val numbers = mutableListOf(1, 2, 3, 4)
println(numbers)
numbers.retainAll { it >= 3 }
println(numbers)
numbers.clear()
println(numbers)
val numbersSet = mutableSetOf("one", "two", "three", "four")
numbersSet.removeAll(setOf("one", "two"))
println(numbersSet)
val numbersMinusOperator = mutableListOf("one", "two", "three", "three", "four")
numbersMinusOperator -= "three"
println(numbersMinusOperator)
numbersMinusOperator -= listOf("four", "five")
// numbersMinusOperator -= listOf("four") // does the same as above
println(numbersMinusOperator)
}
// endregion