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How to check if object (variable) is defined in R?

...een created by a queuing system. These can possibly be addressed with "ls" and its argument "pattern" that expects a regular expression. The "exists" function could be reimplemented that way as exists <-function(variablename) { #print(ls(env=globalenv())) return(1==length(ls(pattern=paste...
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autolayout - make height of view relative to half superview height

have been getting into autolayouts recently and I'm stuck on what seems like a really trivial problem example. I have a view that I want to sit at the top of the screen, and take up half of the screen-height. Simple before autolayout - just tack it in place and tell it to expand vertically when the ...
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Sorting list based on values from another list?

...t should be: The list is ordered regarding the first element of the pairs, and the comprehension extracts the 'second' element of the pairs. – MasterControlProgram Oct 6 '17 at 14:31 ...
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How to get the Full file path from URI

... Use: String path = yourAndroidURI.uri.getPath() // "/mnt/sdcard/FileName.mp3" File file = new File(new URI(path)); or String path = yourAndroidURI.uri.toString() // "file:///mnt/sdcard/FileName.mp3" File file = new File(new URI(path)); ...
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Get encoding of a file in Windows

This isn't really a programming question, is there a command line or Windows tool (Windows 7) to get the current encoding of a text file? Sure I can write a little C# app but I wanted to know if there is something already built in? ...
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Why can't code inside unit tests find bundle resources?

...; Then your code will search the bundle that your unit test class is in, and everything will be fine. share | improve this answer | follow | ...
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Adding placeholder text to textbox

...; myTxtbx.Text = "Enter text here..."; myTxtbx.GotFocus += GotFocus.EventHandle(RemoveText); myTxtbx.LostFocus += LostFocus.EventHandle(AddText); public void RemoveText(object sender, EventArgs e) { if (myTxtbx.Text == "Enter text here...") { myTxtbx.Text = ""; } } public void A...
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LINQ to SQL Left Outer Join

...re-as yours matches only 0-1. To do a left outer join, you need SelectMany and DefaultIfEmpty, for example: var query = from c in db.Customers join o in db.Orders on c.CustomerID equals o.CustomerID into sr from x in sr.DefaultIfEmpty() select new {...
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Is it safe to parse a /proc/ file?

...o even this tiny, trivial file was subject to a race condition until then, and still is in most enterprise kernels. See fs/proc/uptime.c for the current source, or the commit that made it atomic. On a pre-2.6.30 kernel, you can open the file, read a bit of it, then if you later come back and read ...
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Prevent browser caching of AJAX call result

...believe that the DV are made because yours is above Peter's (as accepted). and the OP doesn't appear on SO since early 2013 – Michel Ayres Sep 5 '14 at 13:01 1 ...