CODEWITHSUNDEEP
javascriptjqueryarrays
Cody
Cody

Reputation: 11

An array of arrays confusion

I'm trying to display the levels I'll have using this code...

levelArray[0] = ["player", "empty", "empty", "empty", "wall", "wall", "empty",
    "empty", "wall", "wall", "empty", "empty", "empty","empty",
    "empty", "empty", "empty", "wall", "empty", "wall", "wall",
    "wall", "wall", "empty", "wall", "empty", "wall", "empty",
    "box", "wall", "empty", "wall", "empty", "empty", "empty",
    "empty", "empty", "empty", "wall", "wall", "wall", "empty",
    "wall", "wall", "empty", "empty", "ghost", "wall","ghost"];

for(var i = 0; i < edge; i++)
{
    for(var j = 0; j < edge; j++)
    {
        switch(levelArray[i])
        {
            case "empty":   // empty location
                ctx.drawImage(emptyTile, currentX, currentY);
                break;
            case "wall":    // wall block
                ctx.drawImage(wallTile, currentX, currentY);
                break;
            case "box":     // box block
                ctx.drawImage(boxTile, currentX, currentY);
                break;
            case "ghost":   // enemy sprite
                ctx.drawImage(ghostTile, currentX, currentY);
                break;
            case "player":  // player sprite
                ctx.drawImage(playerTile, currentX, currentY);
                break;
        }
        currentX += elementEdge;
    }
    currentY += elementEdge;
}

however I receive an error on the switch line "Uncaught TypeError: Cannot read property '0' of undefined" and I don't really understand it.

Edit: edge is defined previously like this

edge = Math.sqrt(levelArray.length)

Upvotes: -1

Views: 132

Answers (2)

bfavaretto
bfavaretto

Reputation: 71939

You're not using the inner loop. I believe you want this instead:

switch(levelArray[i][j])

In your source code, that snippet is inside a setupCanvas function, with takes levelArray as an argument. Since you're not passing anything when you call setupCanvas, it's considered undefined. Hence the errors you're getting.

Upvotes: 0

gred
gred

Reputation: 537

Try to access your array of levelArray like this:

switch(levelArray[0][i])

, because this levelArray[i] will return array in case i=0 for sure and other cases of i if you have placed more arrays!

Upvotes: 0

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