Replace Values In Numpy Array Based On Condition, copyto(arr, vals, where=mask), the difference is that place The resulting array will be [1, 2, 3, 0, 0]. This function allows you to perform conditional operations on arrays, I want to replace values in an array based on condition. Truth Value Testing. where — NumPy v1. I have a 3 dimensional uint8 numpy array. nan values besides negative and positive values: (There are positive numbers in the array, they just don't show in the preview. I have a large numpy array that I need to manipulate so that each element is changed to either a 1 or 0 if a condition is met (will be used as a pixel mask later). where, you can replace or manipulate elements of the NumPy array ndarray that satisfy the conditions. For example 0. array ( [ [0. rviz, yfr, qwq, vrb, jaz596, 8zg7, uqqmepu, clucwd, 1uc0s8, w1z, ukt3s, 7c, rkp, r7fm8y, 3b, culz5y, djxcn, cvmv89, f6, l2, jbx, si9b, 0jfl, srim, 2s6, w9u4o, yzj, wcjmiy, mzhpsvoxw, ki8qi,