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How to join (merge) data frames (inner, outer, left, right)
...nner join: merge(df1, df2) will work for these examples because R automatically joins the frames by common variable names, but you would most likely want to specify merge(df1, df2, by = "CustomerId") to make sure that you were matching on only the fields you desired. You can also use the by.x and b...
jQuery: select all elements of a given class, except for a particular Id
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From the documentation: All selectors are accepted inside :not(), for example: :not(div a) and :not(div,a) so just use the comma delimited selectors to do multiple (".thisclass:not(#thisid,#thatid)").doAction();
– Chase
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How do Trigonometric functions work?
...angles between 0 and 45 degrees, you can bootstrap your way to calculating all trig functions for all angles.
Once you've reduced your argument, most chips use a CORDIC algorithm to compute the sines and cosines. You may hear people say that computers use Taylor series. That sounds reasonable, but...
What are good grep tools for Windows? [closed]
Any recommendations on grep tools for Windows? Ideally ones that could leverage 64-bit OS.
28 Answers
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What is the purpose of `text=auto` in `.gitattributes` file?
...f form:
pattern attr1 attr2 ...
So here, the pattern is *, which means all files, and the attribute is text=auto.
What does text=auto do? From the documentation:
When text is set to "auto", the path is marked for automatic end-of-line normalization. If Git decides that the content is text, ...
What is the reason not to use select *?
I've seen a number of people claim that you should specifically name each column you want in your select query.
20 Answers
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What is a difference between
...o it guarantees that when it fetches values from the collection, they will all be E or some subclass (i.e. it's compatible). The drainTo method is trying to put values into the collection, so the collection has to have an element type of E or a superclass.
As an example, suppose you have a class h...
What's your most controversial programming opinion?
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The only "best practice" you should be using all the time is "Use Your Brain".
Too many people jumping on too many bandwagons and trying to force methods, patterns, frameworks etc onto things that don't warrant them. Just because something is new, or because someone r...
How to remove trailing whitespace of all files recursively?
How can you remove all of the trailing whitespace of an entire project? Starting at a root directory, and removing the trailing whitespace from all files in all folders.
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How do I delete all untracked files from my working directory in Mercurial?
Is it possible to delete all untracked files from my working directory? Let's say I added a bunch of files to my working directory, didn't add them via 'hg add' and now want to get rid of those new files entirely?
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