大约有 46,000 项符合查询结果（耗时：0.0387秒） [XML]
What is the best regular expression to check if a string is a valid URL?
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415
I wrote my URL (actually IRI, internationalized) pattern to comply with RFC 3987 (http://www.f...
How can I list (ls) the 5 last modified files in a directory?
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Paul RubelPaul Rubel
24.1k77 gold badges5353 silver badges7676 bronze badges
...
Why does “,,,” == Array(4) in Javascript?
...d operand is converted to a string and the string representation of Array(4) is ,,,:
> Array(4).toString()
",,,"
If you use the array constructor function and pass a number, it sets the length of the array to that number. So you can say you have four empty indexes (same as [,,,]) and the de...
What are the differences between json and simplejson Python modules?
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394
json is simplejson, added to the stdlib. But since json was added in 2.6, simplejson has the adv...
Shuffle two list at once with same order
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answered Apr 25 '14 at 9:45
sshashank124sshashank124
26.6k77 gold badges5353 silver badges6666 bronze badges
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Get the cartesian product of a series of lists?
...hon 2.6.
import itertools
somelists = [
[1, 2, 3],
['a', 'b'],
[4, 5]
]
for element in itertools.product(*somelists):
print(element)
Which is the same as,
for element in itertools.product([1, 2, 3], ['a', 'b'], [4, 5]):
print(element)
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Concatenating two one-dimensional NumPy arrays
... explicit sequences).
– Jim K.
Aug 24 '16 at 20:43
@JimK. What would happen to the axis parameter?
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Can dplyr package be used for conditional mutating?
...f %>%
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 if_else; howev...
ERROR: Error installing capybara-webkit:
...
If you are in Ubuntu do
sudo apt-get install qt4-dev-tools libqt4-dev libqt4-core libqt4-gui
If you are on Mac
brew install qt
and then
gem install capybara-webkit -v '0.11.0'
share
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How to get Top 5 records in SqLite?
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Tim Cooper
138k3434 gold badges286286 silver badges249249 bronze badges
answered Apr 28 '10 at 11:34
NixNix
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