two dots as python argument for slicing : Say I have an array and I want a function to select some of its columns based on an argument **a** that is pre-defined : 

extracted_columns = array[:,a]. 

If I have e.g. **a** = np.arange(10), I'll get the first ten columns, 

What if I want to define a so that all the columns are selected without knowing the size of the array ? 

I'd like to set a = : so that the function does 

extracted_columns = array[:,:]

but it seems : can't pas passed as an argument. I also tried a = None but this gives me an array of dimensions 3 with the second dimension equal to 1.

Is there a nice way of doing it ? 

Thanks, 




