Python Pandas Use if-else to populate new column

I have a data set like this:

col1       col2      
  1          0
  0          1
  0          0
  0          0
  3          3
  2          0
  0          4

I'd like to add a column that is a 1 if col2 is > 0 or 0 otherwise. If I was using R I'd do something like

df1[,'col3'] <- ifelse(df1$col2 > 0, 1, 0)

How would I do this in python / pandas?