How to populate a field by the field name having the maximum value across the rows?

[badrinathkar]

I have a point shapefile that contains five fields including the Id field. Now, I want to find the max value across the rows and populate another row with the field name having the maximum value. How to do this using python?

The table looks like this

Id	X1	X2	X3	X4	MaxValue
1	105	15	11	66
2	62	30	56	25
3	84	22	28	24
4	93	27	89	36
5	71	33	35	77
6	56	54	68	39
7	22	56	71	72
8	81	52	49	41
9	79	29	33	32
10	37	20	73	51

[DanPatterson]

conceptually

vals = [105, 15, 111, 66]

["X1", "X2", "X3", "X4"][vals.index(max(vals))]
'X3'

in practice

vals = [105, 15, 111, 66]

["X1", "X2", "X3", "X4"][vals.index(max(!X1!, !X2!, !X3!, !X4!))]

without actually checking.... obviously a field calculation into a string/text field using python parser

[BlakeTerhune]

Does it matter how ties are broken (if two or more fields have the same maximum value)?

[badrinathkar]

No.

[DanPatterson]

max takes the first