大约有 47,000 项符合查询结果（耗时：0.0681秒） [XML]
Is there a python equivalent of Ruby's 'rvm'?
...|
edited Feb 16 '16 at 11:28
answered May 11 '10 at 16:27
O...
How to get execution time in rails console?
...
242
timing = Benchmark.measure { Post.all }
The various attributes of the object returned (Bench...
Overload constructor for Scala's Case Classes?
In Scala 2.8 is there a way to overload constructors of a case class?
2 Answers
2
...
Count, size, length…too many choices in Ruby?
...ke an element or predicate and count only those items that match.
> [1,2,3].count{|x| x > 2 }
=> 1
In the case where you don't provide a parameter to count it has basically the same effect as calling length. There can be a performance difference though.
We can see from the source code...
How do you get the width and height of a multi-dimensional array?
...
247
You use Array.GetLength with the index of the dimension you wish to retrieve.
...
What are the aspect ratios for all Android phone and tablet devices?
...
162
In case anyone wanted more of a visual reference:
Decimal approximations reference table:
...
In Maven 2, how do I know from which dependency comes a transitive dependency?
...
132
To add to @David Crow, here's a dependency:tree example from the Maven site:
mvn dependency:tre...
How to overcome TypeError: unhashable type: 'list'
...pend(value)
else:
d[key] = [value]
print d
# {'AAA': ['111', '112'], 'AAC': ['123'], 'AAB': ['111']}
Note that if you are using Python 3.x, you'll have to make a minor adjustment to get it work properly. If you open the file with rb, you'll need to use line = line.split(b'x') (which mak...
JavaScript exponents
...ll rise a to the power b
Now it is already implemented in Edge14, Chrome52, and also it is available with traceur or babel.
share
|
improve this answer
|
follow
...
Can dplyr package be used for conditional mutating?
...
220
Use ifelse
df %>%
mutate(g = ifelse(a == 2 | a == 5 | a == 7 | (a == 1 & b == 4), 2,
...