for example we have:
| a | b | c |
|---|---|---|
| 1 | 1 | 3 |
| 2 | 4 | 1 |
| 3 | 2 | 1 |
And now using python I’m trying to create this:
| a | b | c | max |
|---|---|---|---|
| 1 | 1 | 3 | 3c |
| 2 | 4 | 1 | 4b |
| 3 | 2 | 1 | 3a |
>Solution :
If need match first maximal column join max converted to strings with DataFrame.idxmax for columns names by max:
cols = ['a','b','c']
df['max'] = df[cols].max(axis=1).astype(str).str.cat(df[cols].idxmax(axis=1))
print (df)
a b c max
0 1 1 3 3c
1 2 4 1 4b
2 3 2 1 3a
If possible multiple max values and need all matched columns use DataFrame.dot trick with separator ,:
print (df)
a b c
0 3 1 3
1 2 4 1
2 3 2 1
cols = ['a','b','c']
max1 = df[cols].max(axis=1)
s = df[cols].eq(max1, axis=0).dot(pd.Index(cols) + ',').str[:-1]
df['max'] = max1.astype(str).str.cat(s)
print (df)
a b c max
0 3 1 3 3a,c
1 2 4 1 4b
2 3 2 1 3a