Python Pandas：使用浮点数和字符/字母从df获取单个最大数值

Question

I want to get the single max numeric value from this df below which contains a mix of floats and characters/alphas.

Here is my df:

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 outcome:

43.0

At the moment I am creating a new df which excludes "group1" and "group2" but there must be a better way to pull the max numeric value?

Note: this thread is linked to http://goo.gl/ZJoR9V

Thanks

Answer 1

Using 0.14.1, this is a nice clean way

In [6]: df.select_dtypes(exclude=['object']).max().max()
Out[6]: 43.0

Or

In [6]: df.select_dtypes(exclude=['object']).unstack().max()
Out[6]: 43.0