Get the size of a 2D array

java arrays multidimensional-array
William picture William · Nov 6, 2010 · Viewed 173.6k times · Source

Okay, so I have a 2D array z[50][50] and z's size is therefore 50 * 50, but if I say z.length I only get 50 back. How do I get the real size of a 2D array?

Answer

Mark Elliot picture Mark Elliot · Nov 6, 2010

In Java, 2D arrays are really arrays of arrays with possibly different lengths (there are no guarantees that in 2D arrays that the 2nd dimension arrays all be the same length)

You can get the length of any 2nd dimension array as z[n].length where 0 <= n < z.length.

If you're treating your 2D array as a matrix, you can simply get z.length and z[0].length, but note that you might be making an assumption that for each array in the 2nd dimension that the length is the same (for some programs this might be a reasonable assumption).

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