Convert spark DataFrame column to python list

I work on a dataframe with two column, mvv and count.

    +---+-----+
    |mvv|count|
    +---+-----+
    | 1 |  5  |
    | 2 |  9  |
    | 3 |  3  |
    | 4 |  1  |

i would like to obtain two list containing mvv values and count value. Something like

    mvv = [1,2,3,4]
    count = [5,9,3,1]

So, I tried the following code: The first line should return a python list of row. I wanted to see the first value:

    mvv_list = mvv_count_df.select('mvv').collect()
    firstvalue = mvv_list[0].getInt(0)

But I get an error message with the second line:

AttributeError: getInt

See, why this way that you are doing is not working. First, you are trying to get integer from a Row Type, the output of your collect is like this:

    >>> mvv_list = mvv_count_df.select('mvv').collect()
    >>> mvv_list[0]
    Out: Row(mvv=1)

If you take something like this:

    >>> firstvalue = mvv_list[0].mvv
    Out: 1

You will get the mvv value. If you want all the information of the array you can take something like this:

    >>> mvv_array = [int(row.mvv) for row in mvv_list.collect()]
    >>> mvv_array
    Out: [1,2,3,4]

But if you try the same for the other column, you get:

    >>> mvv_count = [int(row.count) for row in mvv_list.collect()]
    Out: TypeError: int() argument must be a string or a number, not 'builtin_function_or_method'

This happens because count is a built-in method. And the column has the same name as count. A workaround to do this is change the column name of count to _count:

    >>> mvv_list = mvv_list.selectExpr("mvv as mvv", "count as _count")
    >>> mvv_count = [int(row._count) for row in mvv_list.collect()]

But this workaround is not needed, as you can access the column using the dictionary syntax:

    >>> mvv_array = [int(row['mvv']) for row in mvv_list.collect()]
    >>> mvv_count = [int(row['count']) for row in mvv_list.collect()]

And it will finally work!

From: stackoverflow.com/q/38610559