[英]Accessing data in array with variable returns undefined, whereas a hardcoded number returns the expected object
我目前正在學習 typescript 作為我的第二語言,並且對 arrays 有一些問題。
與使用硬編碼數字訪問列表相比,使用變量訪問列表時我發現非常奇怪的行為。
我的代碼如下:
class Game {
data: Array<Array<cell>>;
size: number;
constructor () {
this.data = [];
this.size = 20;
}
initialiseGame() {
// here we create an array of arrays full of cells
this.data = []
for (let row = 0; row < this.size; row++) {
this.data.push([]);
for (let col = 0; col < this.size; col++){
this.data[row][col] = new cell(row, col);
}
// console.log here prints the data as I would expect
this.plantBombs();
}
getRandomInt(max: number): number {
return Math.floor(Math.random() * max)
}
plantBombs() {
let randomX, randomY, bombsPlanted = 0;
while (bombsPlanted < this.bombs){
randomX = this.getRandomInt(this.size);
randomY = this.getRandomInt(this.size);
// console.log(this.data[0][0]) gives the expected value
// this.data[randomX] gives undefined
// this.data[randomX][randomY] raises the error can not read properties of undefined
if (!this.data[randomX][randomY].isMine){
this.data[randomX][randomY].isMine = true;
bombsPlanted ++;
}
}
}
}
我使用Number.isInteger
來檢查該值是否為 int,我還嘗試將this.data
傳遞給plantBombs
我訪問數組data
的方式是否不正確,或者我在這里錯過了一些簡單的事情?
你在錯誤的地方調用plantBombs
this.data = [];
for (let row = 0; row < this.size; row++) {
this.data.push([]);
for (let col = 0; col < this.size; col++) {
this.data[row][col] = new cell(row, col);
}
// was there
}
// should be here
this.plantBombs();
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