Quick way to check if the pandas series contains a negative value

Question

What is the quickest way to check if the given pandas series contains a negative value.

For example, for the series s below the answer is True.

s = pd.Series([1,5,3,-1,7])

0    1
1    5
2    3
3   -1
4    7
dtype: int64

`(s<0).sum()>0` ? – Vivek Kalyanarangan Aug 07 '18 at 07:09 — Vivek Kalyanarangan, Aug 07 '18 at 07:09
Even shorter - `(s<0).any()` – Vivek Kalyanarangan Aug 07 '18 at 07:10 — Vivek Kalyanarangan, Aug 07 '18 at 07:10
Even shorter - `any(s<0)` – Mohit Motwani Aug 07 '18 at 07:17 — Mohit Motwani, Aug 07 '18 at 07:17

score 19 · Accepted Answer · answered Aug 07 '18 at 07:09

19

Use any

>>> s = pd.Series([1,5,3,-1,7])
>>> any(s<0)
True

answered Aug 07 '18 at 07:09

Sunitha

Of all the answers, this is the fastest. – Mohit Motwani Aug 07 '18 at 07:16
@MohitMotwani that depends on the size of the series and the index of the item less than zero. – Van Peer Aug 07 '18 at 13:27
@VanPeer In that case, is there a universal fastest answer to this? – Mohit Motwani Aug 07 '18 at 13:56
Plus where would this method be slower compared to the other methods mentioned? – Mohit Motwani Aug 07 '18 at 14:02

Joe · Answer 2 · 2018-08-07T07:15:34.190

5

You can use Series.lt :

s = pd.Series([1,5,3,-1,7])
s.lt(0).any()

Output:

True

edited Aug 07 '18 at 07:15

answered Aug 07 '18 at 07:10

Joe

score 0 · Answer 3 · answered Aug 07 '18 at 07:12

0

Use any function:

>>>s = pd.Series([1,5,3,-1,7])
>>>any(x < 0 for x in s)
True
>>>s = pd.Series([1,5,3,0,7])
>>>any(x < 0 for x in s)
False

answered Aug 07 '18 at 07:12

mastisa

3 Answers3