如何检查 MutableList 的元素或 String 输入是数字？

Question

我运行在下面的代码中遇到了问题。

fun main() {
val table = mutableListOf(
    mutableListOf(' ', ' ', ' '),
    mutableListOf(' ', ' ', ' '),
    mutableListOf(' ', ' ', ' ')
)

println("---------")
println("| " + table[0][0] + " " + table[0][1] + " " + table[0][2] + " |")
println("| " + table[1][0] + " " + table[1][1] + " " + table[1][2] + " |")
println("| " + table[2][0] + " " + table[2][1] + " " + table[2][2] + " |")
println("---------")

print("Enter the coordinates: ")
var coordinates = readLine()!!.split(" ").toMutableList()
var x = coordinates[0].toInt()
var y = coordinates[1].toInt()


while (x > 3 || x < 1 || y > 3 || y < 1) {
    println("Coordinates should be from 1 to 3!")
    print("Enter the coordinates: ")
    coordinates = readLine()!!.split(" ").toMutableList()
    x = coordinates[0].toInt()
    y = coordinates[1].toInt()
}

while (table[x-1][y-1] == 'X' || table[x-1][y-1] == 'O') {
    println("This cell is occupied! Choose another one!")
    print("Enter the coordinates: ")
    coordinates = readLine()!!.split(" ").toMutableList()
    x = coordinates[0].toInt()
    y = coordinates[1].toInt()
}

table[x-1][y-1] = 'X'

println("---------")
println("| " + table[0][0] + " " + table[0][1] + " " + table[0][2] + " |")
println("| " + table[1][0] + " " + table[1][1] + " " + table[1][2] + " |")
println("| " + table[2][0] + " " + table[2][1] + " " + table[2][2] + " |")
println("---------")


if (table[0][0] == 'X' && table[0][1] == 'X' && table[0][2] == 'X' ||
    table[1][0] == 'X' && table[1][1] == 'X' && table[1][2] == 'X' ||
    table[2][0] == 'X' && table[2][1] == 'X' && table[2][2] == 'X' ||
    table[0][0] == 'X' && table[1][0] == 'X' && table[2][0] == 'X' ||
    table[0][1] == 'X' && table[1][1] == 'X' && table[2][1] == 'X' ||
    table[0][2] == 'X' && table[1][2] == 'X' && table[2][2] == 'X' ||
    table[0][0] == 'X' && table[1][1] == 'X' && table[2][2] == 'X' ||
    table[2][0] == 'X' && table[1][1] == 'X' && table[0][2] == 'X'
) {
    println("X wins")
} else if (table[0][0] == 'O' && table[0][1] == 'O' && table[0][2] == 'O' ||
    table[1][0] == 'O' && table[1][1] == 'O' && table[1][2] == 'O' ||
    table[2][0] == 'O' && table[2][1] == 'O' && table[2][2] == 'O' ||
    table[0][0] == 'O' && table[1][0] == 'O' && table[2][0] == 'O' ||
    table[0][1] == 'O' && table[1][1] == 'O' && table[2][1] == 'O' ||
    table[0][2] == 'O' && table[1][2] == 'O' && table[2][2] == 'O' ||
    table[0][0] == 'O' && table[1][1] == 'O' && table[2][2] == 'O' ||
    table[2][0] == 'O' && table[1][1] == 'O' && table[0][2] == 'O'
) {
    println("O wins")
}

}

我可以检查输入是否小于或大于 3（坐标），也可以检查该字段是否未被占用。但是我如何检查输入不是带有 while 循环的字符串，比如检查字段占用和坐标。提前致谢！

Answer 1

我建议这样做

x = coordinates[0].toIntOrNull() ?: 99
y = coordinates[1].toIntOrNull() ?: 99

与toInt()和toIntOrNull()的区别在于toIntOrNull()在无法将其转换为Int但会return null时不会抛出异常反而。这可以使用 elvis 运算符 ?: 重定向到后备号码。在这里你可以放任何不在你要求的 1-3 范围内的东西。我只是选择 99 来演示这一点。

Answer 2

我是这样做的：

print("Enter the coordinates: ")
var coordinates = readLine()!!.split(" ").toMutableList()


while (coordinates[0].length > 1 || coordinates[1].length > 1 || coordinates[0].length > 1 && coordinates[1].length > 1 ) {
    println("You should enter numbers!")
    print("Enter the coordinates: ")
    coordinates = readLine()!!.split(" ").toMutableList()
}

如何检查 MutableList 的元素或 String 输入是数字？

How to check a MutableList's element or a String input is a number?

string

function

kotlin

mutablelist