How to check if any value of a column is in a rang

问题:

I have a DataFrame and I would like to check if any of the values (v) of a column satisfies x<=v<=y.

equal = any(df['columnX'] == value) # No problems here
in_between = any(x <= df['columnX'] <= y) # ValueError :/

The error I get is ValueError: The truth value of a Series is ambiguous. Use a.empty, a.bool(), a.item(), a.any() or a.all(). But I am using any() already!

So what's the problem here? Why does it work with == but not with x<=v<=y?

回答1:

Use between to do this, it also supports whether the range values are included or not via inclusive arg:

In [130]:
s = pd.Series(np.random.randn(5))
s

Out[130]:
0   -0.160365
1    1.496937
2   -1.781216
3    0.088023
4    1.325742
dtype: float64

In [131]:
s.between(0,1)

Out[131]:
0    False
1    False
2    False
3     True
4    False
dtype: bool

You then call any on the above:

In [132]:
s.between(0,1).any()

Out[132]:
True

回答2:

You can just have two conditions:

df[(x <= df['columnX']) & (df['columnX'] <= y)]

This line will select all rows in df where the condition is satisfied.

回答3:

If you like to see other column values, you could try

df.loc[ df.loc[:, 'columnX'].between(a, b), : ]