创建P5.js二维数组 [英] Creating a P5.js 2-Dimensional Array

问题描述

我正在尝试将我的工作处理草图移植到p5.js，以便我可以在线使用它。但是当我尝试在二维数组中设置值时，我遇到了一个问题。我想我正在遵循API的2d数组部分中显示的正确语法，但是我得到一个未被捕获的类型错误，上面写着无法设置未定义的属性0。

I'm trying to port my working processing sketch to p5.js so I can use it online. But I'm running into a problem when trying to set the values in a 2 dimensional array. I think I'm following the correct syntax shown in the 2d array section of the API, but am getting an uncaught type error that says "cannot set property 0 of undefined".

草图非常简单，我只是想从CSV中读取并将数据存储在2D数组中：

The sketch is pretty simple, I'm just trying to read from a CSV and store the data in a 2D array:

var cols = 8;
var rows = 8;
var month = 1;
var values = [];
var table;

function preload(){
    table = loadTable("1988.csv", "csv");
}

function setup() {
    createCanvas(800, 800);
    var totalRows = table.getRowCount();

    for (var m = 0; m < 12; m++) {
        for (var c = 0; c < cols; c++) {
            values[c]=[];
            for (var r = 0; r < rows; r++) {
                values[r+m*rows][c] = table.getNum(m*rows*cols + c*rows + r, 0);
            }
        }
    }
}

任何非常感谢帮助！

感谢您的时间。

推荐答案

尝试在将数组访问值设置为 undefined 对象之前分配数组：

Try allocating the array before setting array access values to undefined objects:

var cols = 8;
var rows = 8;
var month = 1;
var months = 12;
var values = new Array(months);
var table;

function preload(){
    table = loadTable("1988.csv", "csv");
    for(var i = 0 ; i < months; i++) values[i] = [];//initialize 2nd dimension of the array as well, not just the 1st
}

function setup() {
    createCanvas(800, 800);
    var totalRows = table.getRowCount();

    for (var m = 0; m < 12; m++) {
        for (var c = 0; c < cols; c++) {
            values[c]=[];
            for (var r = 0; r < rows; r++) {
                values[r+m*rows][c] = table.getNum(m*rows*cols + c*rows + r, 0);
            }
        }
    }
}

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