push() a two-dimensional array

You have some errors in your code: Use myArray[i].push( 0 ); to add a new column. Your code (myArray[i][j].push(0);) would work in a 3-dimensional array as it tries to add another element to an array at position [i][j]. You only expand (col-d)-many columns in all rows, even in those, which haven’t been initialized yet and … Read more

Change the values of a NumPy array that are NOT in a list of indices

I don’t know of a clean way to do something like this: mask = np.ones(a.shape,dtype=bool) #np.ones_like(a,dtype=bool) mask[indices] = False a[~mask] = 999 a[mask] = 888 Of course, if you prefer to use the numpy data-type, you could use dtype=np.bool_ — There won’t be any difference in the output. it’s just a matter of preference really.

Why is an ArrayList of ArrayLists not multidimensional?

Cay S. Horstmann has stated within his book Core Java for the impatient: There are no two-dimensional array lists in Java, but you can declare a variable of type ArrayList<ArrayList<Integer>> and build up the rows yourself. due to the fact that ArrayLists can expand and shrink and become jagged rather than multi-dimensional, one could say … Read more

How to iterate through array of objects in Swift?

I would try this: var array:[[Person]] = [[person1, person2, person3], [person9, person10, person11]] /*Casting it like this should keep from getting an error later and/or having to recast the objects*/ for people in array { /*This is going to look at each array in arrays, and call each one ‘people’ within this loop*/ for person … Read more