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How do I compute derivative using Numpy?
How do I calculate the derivative of a function, for example
8 Answers
8
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How to sum a variable by group
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Using aggregate:
aggregate(x$Frequency, by=list(Category=x$Category), FUN=sum)
Category x
1 First 30
2 Second 5
3 Third 34
In the example above, multiple dimensions can be specified in the list. Multiple aggregated metrics of the same data type can be incorporated via cbind:
ag...
select、poll、epoll之间的区别总结[整理] - C/C++ - 清泛网 - 专注C/C++及内核技术
...echo程序进行了测试。连接如下所示：
select：http://www.cnblogs.com/Anker/archive/2013/08/14/3258674.html
poll：http://www.cnblogs.com/Anker/archive/2013/08/15/3261006.html
epoll：http://www.cnblogs.com/Anker/archive/2013/08/17/3263780.html
今天对这三种IO多路复用进...
How does the “this” keyword work?
...t("I'm evaluated in the initial global execution context!");
setTimeout(function () {
alert("I'm NOT evaluated in the initial global execution context.");
}, 1);
</script>
When evaluating code in the initial global execution context, ThisBinding is set to the global object, window ...
Undefined, unspecified and implementation-defined behavior
...tandard as unspecified (for example, order of evaluation of arguments to a function). Where possible, this International Standard defines a set of allowable behaviors. These define the nondeterministic aspects of the abstract machine.
Certain other operations are described in this International Stan...
How can I change the language (to english) in Oracle SQL Developer?
... this option will be:
oracle.translated.locales = de,es,it,ja,ko,pt_BR,zh_CN,zh_TW
The original value was:
oracle.translated.locales = de,fr,es,it,ja,ko,pt_BR,zh_CN,zh_TW
The configuration above (sqldeveloper.conf file) will be wrong after remove french support and the french language does not...
C++STL容器使用经验总结 - C/C++ - 清泛网 - 专注C/C++及内核技术
...ack(RCSPW(new Widget));
...
v.erase(remove_if(v.begin(),v.end(),not1(mem_fun(&Widget::isCertified))),v.end());
第34条：了解哪些算法要求使用排序的区间作为参数。
下面的代码要求排序的区间：
binary_search lower_bound
upper_bound equal_range
set_union set_...
List all developers on a project in Git
...committer and author), you could use git log:
git log --pretty="%an %ae%n%cn %ce" | sort | uniq
%an author name
%ae author email
%n new line
%cn committer name
%ce committer email
Other placeholders are described in the pretty print documentation of git log.
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Trusting all certificates with okHttp
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Update OkHttp 3.0, the getAcceptedIssuers() function must return an empty array instead of null.
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https connection using CURL from command line
...ificate:
* subject: C=US; ST=California; L=Mountain View; O=Google Inc; CN=www.google.com
* start date: 2016-01-07 11:34:33 GMT
* expire date: 2016-04-06 00:00:00 GMT
* issuer: C=US; O=Google Inc; CN=Google Internet Authority G2
* SSL certificate verify ok.
* Server GFE/2.0 is not bla...