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dplyr summarise: Equivalent of “.drop=FALSE” to keep groups with zero length in output
...e to go with @Moody_Mudskipper's answer: Using .drop=FALSE can give potentially unexpected results when one or more grouping variables are not coded as factors. See examples below:
library(dplyr)
data(iris)
# Add an additional level to Species
iris$Species = factor(iris$Species, levels=c(levels(ir...
Boolean operators && and ||
...es the longer form "appropriate for programming control-flow and [is] typically preferred in if clauses."
So you want to use the long forms only when you are certain the vectors are length one.
You should be absolutely certain your vectors are only length 1, such as in cases where they are funct...
Remove the first character of a string
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@Spaceghost: The OP states "Specifically I want to remove the first character."
– Sven Marnach
Feb 9 '11 at 14:27
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Undo a git stash
...ll not reset what is in the staging directory, so you will have to restage all that (which can be annoying if you had just done a complex git add -p
– Nick
Jan 2 '13 at 17:31
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What is the difference between children and childNodes in JavaScript?
...erty of an Element. 1 Only Elements have .children, and these children are all of type Element. 2
However, .childNodes is a property of Node. .childNodes can contain any node. 3
A concrete example would be:
let el = document.createElement("div");
el.textContent = "foo";
el.childNodes.length === ...
How to get git diff with full context?
... the issue, but using a line count promises that it will work for even a small change in a very large file.
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How to get all enum values in Java?
... yourEnums = YourEnumClass.class.getEnumConstants(); solved my problem of calling from a non-static method.
– Jeremy
Jul 21 '17 at 23:33
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How do I find out which computer is the domain controller in Windows programmatically?
...dows, type the following commande:
nltest /dclist:{domainname}
It lists all domain controllers in particular domain
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GitHub: searching through older versions of files
I know that using GitHub I can search through all the current versions of my files in a repo. However, I would also like to search through the older versions of my repo files. For example, say, I used to have a function called get_info() in my code, but deleted it several versions ago, is it possibl...
How can I do DNS lookups in Python, including referring to /etc/hosts?
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I'm not really sure if you want to do DNS lookups yourself or if you just want a host's ip. In case you want the latter,
import socket
print(socket.gethostbyname('localhost')) # result from hosts file
print(socket.gethostbyname('googl...