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Group by multiple columns in dplyr, using string vector input
I'm trying to transfer my understanding of plyr into dplyr, but I can't figure out how to group by multiple columns.
9 Answ...
Store password in TortoiseHg
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Security warning
Although this answer is accepted as of 2017-09-15, it is not a recommended solution. You should never store your passwords in plain text. Use the mercurial_keyring extension instead. See another answer here.
You can c...
How do I check if a property exists on a dynamic anonymous type in c#?
...ype object that I receive as a dynamic from a method
I would like to check in a property exists on that object.
10 Answers
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How to get current relative directory of your Makefile?
I have a several Makefiles in app specific directories like this:
12 Answers
12
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How do you normalize a file path in Bash?
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if you're wanting to chomp part of a filename from the path, "dirname" and "basename" are your friends, and "realpath" is handy too.
dirname /foo/bar/baz
# /foo/bar
basename /foo/bar/baz
# baz
dirname $( dirname /foo/bar/baz )
# /fo...
Validate phone number with JavaScript
I found this code in some website, and it works perfectly. It validates that the phone number is in one of these formats:
(123) 456-7890 or 123-456-7890
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How to convert TimeStamp to Date in Java?
How do I convert 'timeStamp' to date after I get the count in java?
16 Answers
16
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How could the UNIX sort command sort a very large file?
...tails of UNIX Sort command says Unix Sort uses an External R-Way merge sorting algorithm. The link goes into more details, but in essence it divides the input up into smaller portions (that fit into memory) and then merges each portion together at the end.
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What are the rules about using an underscore in a C++ identifier?
It's common in C++ to name member variables with some kind of prefix to denote the fact that they're member variables, rather than local variables or parameters. If you've come from an MFC background, you'll probably use m_foo . I've also seen myFoo occasionally.
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Replace non-numeric with empty string
Quick add on requirement in our project. A field in our DB to hold a phone number is set to only allow 10 characters. So, if I get passed "(913)-444-5555" or anything else, is there a quick way to run a string through some kind of special replace function that I can pass it a set of characters to ...