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Calculate difference in keys contained in two Python dictionaries
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21 Answers
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Assign multiple columns using := in data.table, by group
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162
This now works in v1.8.3 on R-Forge. Thanks for highlighting it!
x <- data.table(a = 1:3, ...
How to slice an array in Bash
Looking the "Array" section in the bash(1) man page, I didn't find a way to slice an array.
4 Answers
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What are the differences between json and simplejson Python modules?
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13 Answers
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Can dplyr package be used for conditional mutating?
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Use ifelse
df %>%
mutate(g = ifelse(a == 2 | a == 5 | a == 7 | (a == 1 & b == 4), 2,
ifelse(a == 0 | a == 1 | a == 4 | a == 3 | c == 4, 3, NA)))
Added - if_else: Note that in dplyr 0.5 there is an if_else function defined so an alternative would be to replace ifelse with i...
All combinations of a list of lists
... need itertools.product:
>>> import itertools
>>> a = [[1,2,3],[4,5,6],[7,8,9,10]]
>>> list(itertools.product(*a))
[(1, 4, 7), (1, 4, 8), (1, 4, 9), (1, 4, 10), (1, 5, 7), (1, 5, 8), (1, 5, 9), (1, 5, 10), (1, 6, 7), (1, 6, 8), (1, 6, 9), (1, 6, 10), (2, 4, 7), (2, 4, 8),...
Remove duplicate elements from array in Ruby
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the Tin Man
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answered Dec 3 '11 at 5:24
Mithun Sasidh...
Print all but the first three columns
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19 Answers
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Pandas index column title or name
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In [8]: df.index.name = 'foo'
In [9]: df.index.name
Out[9]: 'foo'
In [10]: df
Out[10]:
Column 1
foo
Apples 1
Oranges 2
Puppies 3
Ducks 4
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What is the optimal Jewish toenail cutting algorithm?
...ule. Luckily, humans only have five toes per foot*, so there are only 5! = 120 unrestricted sequences.
Python example:
#seq is only valid when consecutive elements in the list differ by at least two.
def isValid(seq):
for i in range(len(seq)-1):
a = seq[i]
b = seq[i+1]
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