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How does one reorder columns in a data frame?

... has four columns like so df[,c(1,2,3,4)]. Note the first comma means keep all the rows, and the 1,2,3,4 refers to the columns. To change the order as in the above question do df2[,c(1,3,2,4)] If you want to output this file as a csv, do write.csv(df2, file="somedf.csv") ...
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How to remove a key from a Python dictionary?

...osentino No, ignoring the return value of a function is not inefficient at all. Quite the opposite – this solution is much faster than the try/except solution if the key does not exist. You might find one or the other easier to read, which is fine. Both are idiomatic Python, so choose whatever ...
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Difference between Activity Context and Application Context

...nformation about the current activity that is necessary to complete those calls. If you show the exact error message, might be able to point to what exactly it needs. But in general, use the activity context unless you have a good reason not to. ...
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Differences between Octave and MATLAB? [closed]

...uctures are. The above link shows several examples where they are syntactically similar or identical, is this true for the whole language? ...
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Filename too long in Git for Windows

...tions. However, you must opt-in to the new behavior. A registry key allows you to enable or disable the new long path behavior. To enable long path behavior set the registry key at HKLM\SYSTEM\CurrentControlSet\Control\FileSystem LongPathsEnabled (Type: REG_DWORD) ...
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How to make links in a TextView clickable?

...ot // respond to user input. To make them active, you need to // call setMovementMethod() on the TextView object. TextView t2 = (TextView) findViewById(R.id.text2); t2.setMovementMethod(LinkMovementMethod.getInstance()); I removed most of the attributes on my TextView to match wh...
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Select parent element of known element in Selenium

...rue. Output: <div class="parent"> //span/ancestor::* - returns all ancestors (including parent). Output: <div class="parent">, <nav class="second_level_ancestor">, <div class="third_level_ancestor">... //span/ancestor-or-self::* - returns all ancestors and current...
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Python code to remove HTML tags from a string [duplicate]

...tifulSoup You could also use BeautifulSoup additional package to find out all the raw text You will need to explicitly set a parser when calling BeautifulSoup I recommend "lxml" as mentioned in alternative answers (much more robust than the default one (i.e. available without additional install) ...
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ASP.NET Identity - HttpContext has no extension method for GetOwinContext

... ARGH! I found it... I didn't have an extra package, called Microsoft.Owin.Host.SystemWeb Once i searched and installed this, it worked. Now - i am not sure if i just missed everything, though found NO reference to such a library or package when going through various tutorials...
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Firebug-like debugger for Google Chrome

...ntrospection, I can do it with Firebug. Now with IE8's new developer mode, all the major browsers have builtin dev modes. Good times. – guns Apr 27 '09 at 9:32 1 ...