Python: How can i find the count of unique dates from a column

Question

    Model             Order_Date    Units_Sold
0   Blue Widget      2020-06-01     3
1   Green Widget     2020-06-04     4
2   Red Widget       2020-06-04     8 
3   Blue Widget      2020-06-02     3
4   Blue Widget      2020-06-03     5
5   Red Widget       2020-06-03     7
6   Green Widget     2020-06-04     3
7   Red Widget       2020-06-02     5
8   Green Widget     2020-06-01     7

Hey guys, So what I am trying to do is get the count of dates from the unique "order_dates" in Python. So this one is looking at 2020-06-01 to 2020-06-04, so count of 4. I want to be able to save this to a variable, thanks.

score 1 · Answer 1 · answered Jun 12 '20 at 03:51

1

Suppose your DataFrame is named df. Then try:

len(df['Order_Date'].unique())

The .unique() function can be used to get exactly 1 instance of each unique value from a pandas Series column. Then, you can just take the len of that array to get the number of unique values.

answered Jun 12 '20 at 03:51

nathan.j.mcdougall

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Why don't do `df["Order_Date"].nunique()` instead? – Henry Yik Jun 12 '20 at 03:56
@HenryYik No reason! I didn't know about that function, indeed that's a better choice. – nathan.j.mcdougall Jun 13 '20 at 04:24
Perfect, both of these work! Would upvote but stackoverflow wont let me since im new. Thanks guys! – Nuvol Jun 13 '20 at 04:26

score 0 · Answer 2 · answered Jun 12 '20 at 03:55

0

You can also use groupby like so:

count = df.groupby(by=['Model'], axis=0).count()

answered Jun 12 '20 at 03:55

NotAName

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Python: How can i find the count of unique dates from a column

2 Answers2