Boosted_d16 Boosted_d16 - 1 year ago 135
Python Question

return max value from panda dataframe as a whole, not based on column or rows

I am trying to get the max value from a panda dataframe as whole. I am not interested in what row or column it came from. I am just interested in a single max value within the dataframe.

Here is my dataframe:

df = pd.DataFrame({'group1': ['a','a','a','b','b','b','c','c','d','d','d','d','d'],
'group2': ['c','c','d','d','d','e','f','f','e','d','d','d','e'],
'value1': [1.1,2,3,4,5,6,7,8,9,1,2,3,4],
'value2': [7.1,8,9,10,11,12,43,12,34,5,6,2,3]})

This is what it looks like:

group1 group2 value1 value2
0 a c 1.1 7.1
1 a c 2.0 8.0
2 a d 3.0 9.0
3 b d 4.0 10.0
4 b d 5.0 11.0
5 b e 6.0 12.0
6 c f 7.0 43.0
7 c f 8.0 12.0
8 d e 9.0 34.0
9 d d 1.0 5.0
10 d d 2.0 6.0
11 d d 3.0 2.0
12 d e 4.0 3.0

Expected output:


I was under the assumption that df.max() would do this job but it returns a max value for each column but I am not interested in that. I need the max from an entire dataframe.

Answer Source

The max of all the values in the DataFrame can be obtained using df.values.max():

In [10]: df.values.max()
Out[10]: 'f'

The max is f rather than 43.0 since, in CPython2,

In [11]: 'f' > 43.0
Out[11]: True

In CPython2, Objects of different types ... are ordered by their type names. So any str compares as greater than any int since 'str' > 'int'.

In Python3, comparison of strings and ints raises a TypeError.

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