Problems mapping a series to a min(list, key=lambda x: abs(series)) function

Question

I want to find a number in series, and find which number it's closest to in [1,2,3]. Then use the key to replace the series value with the appropriate letter.

key = {1: 'A', 2:'B', 3:'C')
series = pd.Series([x*1.2 for x in range(10)])


pd.DataFrame = key[min([1,2,3], key=lambda x: abs(x-series))]

The series is a column from the pd.DataFrame, I've just tried to simplify it for here.

Answer 1

use the apply method and then map your Series such has:

key = {1: 'A', 2:'B', 3:'C'}
series = pd.Series([x*1.2 for x in range(10)])

def find(myNumber):
    return min([1,2,3], key=lambda x:abs(x-myNumber))

series.apply(find).map(key)
Out[50]: 
0    A
1    A
2    B
3    C
4    C
5    C
6    C
7    C
8    C
9    C
dtype: object

it also should work if you replace series by the entire dataframe such has:

df.apply(find).map(key)