大约有 41,200 项符合查询结果（耗时：0.0289秒） [XML]
Bootstrap 3 Glyphicons are not working
I downloaded bootstrap 3.0 and can't get the glyphicons to work. I get some kind of "E003" error. Any ideas why this is happening? I tried both locally and online and I still get the same problem.
...
How to update Identity Column in SQL Server?
...n the identity column
INSERT INTO YourTable(IdentityCol, otherCol) VALUES(13,'myValue')
GO
-- Delete the old row of which you have inserted a copy (above) (make sure about FK's)
DELETE FROM YourTable WHERE ID=3
GO
--Now set the idenetity_insert OFF to back to the previous track
SET IDENTITY_INSERT Y...
How to get the nth element of a python list or a default if not available
...
gruszczygruszczy
35.8k2626 gold badges113113 silver badges163163 bronze badges
...
Pass a data.frame column name to a function
... just use the column name directly:
df <- data.frame(A=1:10, B=2:11, C=3:12)
fun1 <- function(x, column){
max(x[,column])
}
fun1(df, "B")
fun1(df, c("B","A"))
There's no need to use substitute, eval, etc.
You can even pass the desired function as a parameter:
fun1 <- function(x, colu...
Numpy array dimensions
...
513
It is .shape:
ndarray.shape
Tuple of array dimensions.
Thus:
>>> a.shape
(2, 2...
How do I add the contents of an iterable to a set?
...
231
You can add elements of a list to a set like this:
>>> foo = set(range(0, 4))
>>...
Syntax error on print with Python 3 [duplicate]
Why do I receive a syntax error when printing a string in Python 3?
3 Answers
3
...
汇编语言（王爽著）附书签 - 文档下载 - 清泛网 - 专注C/C++及内核技术
...自己学，看了很多书，国内像这样的好书真的是很难得。3、更珍贵的是老师的编排，可以说比国外的还好（当然从知识点来说不如国外的书，但是这是一本入门书）
我的感想：1、计算机科学方面的好书，中国基本上没有（运...
How can I force division to be floating point? Division keeps rounding down to 0?
...
In Python 2, division of two ints produces an int. In Python 3, it produces a float. We can get the new behaviour by importing from __future__.
>>> from __future__ import division
>>> a = 4
>>> b = 6
>>> c = a / b
>>> c
0.66666666666666663
...
Why can't R's ifelse statements return vectors?
...tors, you will get longer results:
> ifelse(c(TRUE, FALSE), c(1, 2), c(3, 4))
[1] 1 4
So ifelse is intended for the specific purpose of testing a vector of booleans and returning a vector of the same length, filled with elements taken from the (vector) yes and no arguments.
It is a common con...