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Select rows of a matrix that meet a condition
...a frame using as.data.frame(). In that case the previous answers (using subset or m$three) will work, otherwise they will not.
To perform the operation on a matrix, you can define a column by name:
m[m[, "three"] == 11,]
Or by number:
m[m[,3] == 11,]
Note that if only one row matches, the re...
How do I remove the old history from a git repository?
...o/grafts
After creating the graft, it takes effect right away; you should be able to look at git log and see that the unwanted old commits have gone away:
$ echo 4a46bc886318679d8b15e05aea40b83ff6c3bd47 > .git/info/grafts
$ git log --decorate | tail --lines=11
commit cb3da2d4d8c3378919844b29e81...
How to convert URL parameters to a JavaScript object?
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Edit
This edit improves and explains the answer based on the comments.
var search = location.search.substring(1);
JSON.parse('{"' + decodeURI(search).replace(/"/g, '\\"').replace(/&/g, '","').replace(/=/g,'":"') + '"}')
Example
Parse abc=foo&def=%5Basf%5D&x...
How does a “stack overflow” occur and how do you prevent it?
How does a stack overflow occur and what are the best ways to make sure it doesn't happen, or ways to prevent one, particularly on web servers, but other examples would be interesting as well?
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Parse rfc3339 date strings in Python? [duplicate]
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You can use dateutil.parser.parse to parse strings into datetime objects.
dateutil.parser.parse will attempt to guess the format of your string, if you know the exact format in advance then you can use datetime.strptime which you supply a format string to (see Brent Washburne's answer).
f...
A std::map that keep track of the order of insertion?
... the map to print out the values, they are sorted according to the string; but I want them to be sorted according to the order of (first) insertion.
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How to use php serialize() and unserialize()
My problem is very basic.
10 Answers
10
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使用Activity启动器组件 · App Inventor 2 中文网
...件比使用 ActivityStarter 更方便。
启动网络搜索
要启动 Web 搜索，请使用带有 WEB_SEARCH 操作的 ActivityStarter。 用户的手机将显示一个菜单，询问要执行哪种搜索：
Action：android.intent.action.WEB_SEARCH
打开浏览器到指定网页：将这些 ...
Big-O for Eight Year Olds? [duplicate]
I'm asking more about what this means to my code. I understand the concepts mathematically, I just have a hard time wrapping my head around what they mean conceptually. For example, if one were to perform an O(1) operation on a data structure, I understand that the number of operations it has to p...
What is LINQ and what does it do? [closed]
What is LINQ? I know it's for databases, but what does it do?
7 Answers
7
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