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Pandas dataframe get first row of each group
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248
>>> df.groupby('id').first()
value
id
1 first
2 first
3 first
4 ...
Rails Migration: Remove constraint
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answered Apr 15 '11 at 20:42
Paul SturgessPaul Sturgess
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Pandas get topmost n records within each group
... value
id
1 0 1 1
1 1 2
2 3 2 1
4 2 2
3 7 3 1
4 8 4 1
(Keep in mind that you might need to order/sort before, depending on your data)
EDIT: As mentioned by the questioner, use df.groupby('id').head(2).reset_index(drop=True) to remo...
What does upstream mean in nginx?
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Bahrom
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answered May 4 '11 at 2:56
Phil LelloPhil Lello
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RedirectToAction between areas?
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answered Sep 8 '09 at 5:41
eu-ge-neeu-ge-ne
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Clojure: cons (seq) vs. conj (list)
...ts to insert into a collection, while cons takes just one:
(conj '(1 2 3) 4 5 6)
; => (6 5 4 1 2 3)
(cons 4 5 6 '(1 2 3))
; => IllegalArgumentException due to wrong arity
Another difference is in the class of the return value:
(class (conj '(1 2 3) 4))
; => clojure.lang.PersistentList
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