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Single Line Nested For Loops
...hension (here (x,y)):
>>> [(x, y) for x in [1,2,3] for y in [3,1,4] if x != y]
[(1, 3), (1, 4), (2, 3), (2, 1), (2, 4), (3, 1), (3, 4)]
It's exactly the same as this nested for loop (and, as the tutorial says, note how the order of for and if are the same).
>>> combs = []
>&...
MySql: Tinyint (2) vs tinyint(1) - what is the difference?
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4 Answers
4
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while (1) vs. while(True) — Why is there a difference (in python 2 bytecode)?
...True is reassignable:
Python 2.7 (r27:82508, Jul 3 2010, 21:12:11)
[GCC 4.0.1 (Apple Inc. build 5493)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> True = 4
>>> True
4
In Python 3.x it truly becomes a keyword and a real constant:
Pyth...
How can I delete one element from an array by value
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490
I think I've figured it out:
a = [3, 2, 4, 6, 3, 8]
a.delete(3)
#=> 3
a
#=> [2, 4, 6, 8...
With bash, how can I pipe standard error into another process?
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edited Jul 1 '14 at 19:06
mmlb
74777 silver badges2323 bronze badges
answered Mar 27 '12 at 1...
Order data frame rows according to vector with specific order
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Try match:
df <- data.frame(name=letters[1:4], value=c(rep(TRUE, 2), rep(FALSE, 2)))
target <- c("b", "c", "a", "d")
df[match(target, df$name),]
name value
2 b TRUE
3 c FALSE
1 a TRUE
4 d FALSE
It will work as long as your target contains exactly...
Active Record - Find records which were created_at before today
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4 Answers
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get list from pandas dataframe column
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534
Pandas DataFrame columns are Pandas Series when you pull them out, which you can then call x.tol...
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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