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What is the purpose of setting a key in data.table?
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A key is basically an index into a dataset, which allows for very fast and efficient sort, filter, and join operations. These are probably the best reasons to use data tables instead of data frames (the syntax for using data tables is also much mo...
Warning the user/local/mysql/data directory is not owned by the mysql user
...restart.
Reference: https://coolestguidesontheplanet.com/get-apache-mysql-php-phpmyadmin-working-osx-10-10-yosemite/
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How do I change an HTML selected option using JavaScript?
...).options[0].selected = 'selected';
}
/**
* Set Select Box Selection By Index
* @param eid Element ID
* @param eindx Element Index
*/
function setSelectBoxByIndex(eid, eindx) {
document.getElementById(eid).getElementsByTagName('option')[eindx].selected = 'selected';
//or
document....
What is the purpose of backbone.js?
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Backbone.js is basically an uber-light framework that allows you to structure your Javascript code in an MVC (Model, View, Controller) fashion where...
Model is part of your code that retrieves and populates the data,
View is the HTML repres...
OS X: equivalent of Linux's wget
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Use curl;
curl http://127.0.0.1:8000 -o index.html
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Remove the first character of a string
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deleting a char:
def del_char(string, indexes):
'deletes all the indexes from the string and returns the new one'
return ''.join((char for idx, char in enumerate(string) if idx not in indexes))
it deletes all the chars that are in indexes; you can use...
Random color generator
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You can remove .split('') call. String already have Array indexer.
– ujeenator
Jul 27 '15 at 6:08
4
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Is a Python list guaranteed to have its elements stay in the order they are inserted in?
...g structure of an Array is still a special case of an object with numbered indexes, so it's not a contradiction to your statement, just an interesting tidbit, I thought.
– Multihunter
Dec 8 '16 at 21:09
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What is polymorphism, what is it for, and how is it used?
...erate on different data types.
The classic example is the Shape class and all the classes that can inherit from it (square, circle, dodecahedron, irregular polygon, splat and so on).
With polymorphism, each of these classes will have different underlying data. A point shape needs only two co-ordin...
std::string截取字符串，截取ip:port - C/C++ - 清泛网 - 专注C/C++及内核技术
...:string截取字符串，截取ip:portstd::string ip("127.0.0.1:8888");int index = ip.find_last_of(':'); 获取ipip.substr(0, index).c_str(); 获取portip.substr(index + 1).c_str();std::string ip("127.0.0.1:8888");
int index = ip.find_last_of(':');
// 获取ip
ip.substr(0, index).c_str();
//...