How to find maximum value in the column using pandas?

Question

This is my code.I will try to read file and find the maximum temperature value(11th column)

import pandas as pd

fn = 'Excel.xlsx'
df = pd.read_excel(fn, header=None)
df1 = df.iloc[:,11:12]
m1 = df.iloc[:,11:12].max()
print (m1)

What I got is not want I wanted

python n0.py 
11    Value
dtype: object

I will show how the 11-th column looks like

0      Value
1      18.71
2      20.86
3      18.37
4       12.3
5       5.54
6       3.96
7       8.33
8      12.23
9      11.02
10      4.18
11      7.62
12     15.06
13        20
14     20.39
15     18.26
16     14.54
17      3.81
18      0.93
19      7.74
20     12.42
21      6.59
22      0.12
23      8.32
24     16.82
25     19.46
26      11.8
27      6.25
28      1.96
29     17.13
       ...  
756    15.59
757     6.82
758     7.48
759    14.99
760    17.61
761    19.48
762     16.8
763     9.65
764     1.63
765     9.26
766    16.25
767    24.85
768    14.08
769     0.11
770     6.56
771    12.75
772    21.94
773    20.57
774    17.97
775    12.73
776     6.16
777     9.12
778    19.03
779    17.39
780    14.06
781     1.76
782     8.25
783    17.41
784    20.61
785    20.73

From these values 24.85 would be the max and it is on 767 position. I have not worked with pandas lately but this was supposed to be simple job. Where is my mistake? Should I use idmax or something else?

Answer 1

First convert column to numeric by to_numeric with errors='coerce' :

and then need for 12 th column:

max = pd.to_numeric(df.iloc[:,11], errors='coerce').max()

and for 11 th need 10 , because python counts from 0 :

max = pd.to_numeric(df.iloc[:,10], errors='coerce').max()