SciPy Recipes

Creating an array by repeating elements

To create arrays with repeated elements, we use the repeat() function, as shown in the following example:

np.repeat(1.2, 3)

This repeats the 1.2 value three times, resulting in the following array:

array([ 1.2,  1.2,  1.2])

The argument to be repeated can be itself an array, as shown in the following example:

x = np.array([[1,2,3],[4,5,6]])y = np.repeat(x, 2)

This will store, in the y variable, the following output array:

array([1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6])

Notice that this version of repeat() flattens the array, that is, it returns a one-dimensional ndarray.  If we want to prevent flattening, we can use the axis option, demonstrated as follows:

y = np.repeat(x, 2, axis=0)

This produces the array: ...