Python: create a new column from existing columns

Question

I am trying to create a new column based on both columns. Say I want to create a new column z, and it should be the value of y when it is not missing and be the value of x when

Answer 1

I'm not sure if I understand the question, but would this be what you're looking for?

"if y[i]" will skip if the value is none.

for i in range(len(x));
    if y[i]:
        z.append(y[i])
    else:
        z.append(x[i])