「Android/kotlin/配列」の版間の差分
提供: 初心者エンジニアの簡易メモ
(→mutableリストに文字列追加) |
(→配列for-in) |
||
| 行1: | 行1: | ||
| − | == | + | ==配列== |
| + | ===for-in=== | ||
<pre> | <pre> | ||
var names:Array<String> | var names:Array<String> | ||
| 行8: | 行9: | ||
} | } | ||
</pre> | </pre> | ||
| + | |||
| + | ===foreach=== | ||
| + | <pre> | ||
| + | names:Array.forEach { | ||
| + | Log.d("test", "name=" + it) | ||
| + | } | ||
==配列プロパティ値取得== | ==配列プロパティ値取得== | ||
2020年10月1日 (木) 16:45時点における版
配列
for-in
var names:Array<String>
if (names.isNotEmpty()) {
for (name: String in names) {
Log.d("test", "name=" + name)
}
}
foreach
names:Array.forEach {
Log.d("test", "name=" + it)
}
==配列プロパティ値取得==
User.kt
<pre>
class User {
var name: String = ""
}
var user = User()
user.name = "taro"
var user2 = User()
user2.name = "jiro"
var users: ArrayList<User> = arrayListOf(user, user2)
var username = users.firstOrNull { it.name.contains("taro") }?.name ?: "" // taro
for (user: User in users) {
Log.i("test", "user.name=" + user.name)
}
配列プロパティ条件一致で更新
var user = User()
user.name = "taro"
var user2 = User()
user2.name = "jiro"
var users: ArrayList<User> = arrayListOf(user, user2)
users.firstOrNull {it.name == "taro"}?.name = "saburo" // taroをsaburoへ
for (user: User in users) {
Log.i("test", "user.name=" + user.name)
}
mutableリストに文字列追加
val names = mutableListOf<String>()
for (i in 1..10000) names.add("name" + i)
