大约有 43,900 项符合查询结果（耗时：0.0405秒） [XML]
How do you calculate log base 2 in Java for integers?
I use the following function to calculate log base 2 for integers:
10 Answers
10
...
What do all of Scala's symbolic operators mean?
...to look for them. Or, failing that, look at the index (presently broken on 2.9.1, but available on nightly).
Every Scala code has three automatic imports:
// Not necessarily in this order
import _root_.java.lang._ // _root_ denotes an absolute path
import _root_.scala._
import _root_.scala.Pr...
SQL RANK() versus ROW_NUMBER()
...
229
ROW_NUMBER : Returns a unique number for each row starting with 1. For rows that have duplicat...
how to check the dtype of a column in python pandas
...
127
You can access the data-type of a column with dtype:
for y in agg.columns:
if(agg[y].dtype...
How to create an object for a Django model with a many to many field?
...
248
You cannot create m2m relations from unsaved objects. If you have the pks, try this:
sample_o...
Iterating over Java collections in Scala
...
28
There is a wrapper class (scala.collection.jcl.MutableIterator.Wrapper). So if you define
imp...
What would cause an algorithm to have O(log n) complexity?
...
290
I have to agree that it's pretty weird the first time you see an O(log n) algorithm... where o...
Sorting arrays in NumPy by column
...ck example, to sort it and return a copy:
In [1]: import numpy as np
In [2]: a = np.array([[1,2,3],[4,5,6],[0,0,1]])
In [3]: np.sort(a.view('i8,i8,i8'), order=['f1'], axis=0).view(np.int)
Out[3]:
array([[0, 0, 1],
[1, 2, 3],
[4, 5, 6]])
To sort it in-place:
In [6]: a.view('i8,i8...
Weighted random numbers
...e items have individual weights:
1) calculate the sum of all the weights
2) pick a random number that is 0 or greater and is less than the sum of the weights
3) go through the items one at a time, subtracting their weight from your random number, until you get the item where the random number is ...
Write a number with two decimal places SQL server
...
218
try this
SELECT CONVERT(DECIMAL(10,2),YOURCOLUMN)
...