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Can dplyr package be used for conditional mutating?
... ifelse(a == 0 | a == 1 | a == 4 | a == 3 | c == 4, 3, NA)))
Added - if_else: Note that in dplyr 0.5 there is an if_else function defined so an alternative would be to replace ifelse with if_else; however, note that since if_else is stricter than ifelse (both legs of the condition must have the ...
How to convert Strings to and from UTF8 byte arrays in Java
...]:
String s = "some text here";
byte[] b = s.getBytes(StandardCharsets.UTF_8);
Convert from byte[] to String:
byte[] b = {(byte) 99, (byte)97, (byte)116};
String s = new String(b, StandardCharsets.US_ASCII);
You should, of course, use the correct encoding name. My examples used US-ASCII and UT...
Scala @ operator
...n itself? That would be accomplished with this:
o match {
case x @ Some(_) => println(x)
case None =>
}
Note that @ can be used at any level, not just at the top level of the matching.
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Function for Factorial in Python
...The concept used here is called recursion ( en.wikipedia.org/wiki/Recursion_(computer_science) ) - a function calling itself is perfectly fine and often useful.
– schnaader
Nov 7 '14 at 10:06
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C++ Dynamic Shared Library on Linux
...
myclass.h
#ifndef __MYCLASS_H__
#define __MYCLASS_H__
class MyClass
{
public:
MyClass();
/* use virtual otherwise linker will try to perform static linkage */
virtual void DoSomething();
private:
int x;
};
#endif
myclass.cc
#inc...
Python None comparison: should I use “is” or ==?
My editor warns me when I compare my_var == None , but no warning when I use my_var is None .
3 Answers
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Unable to install Maven on Windows: “JAVA_HOME is set to an invalid directory”
...e-maven-2.2.0\bin" is on your command search path.
Make sure that the JAVA_HOME variable refers to the home directory for your Java installation. If you are executing Java from "E:\Sun\SDK\jdk\bin", then the JAVA_HOME variable needs to point to "E:\Sun\SDK\jdk".
NB: JAVA_HOME should NOT end with "...
What is the definition of “interface” in object oriented programming
...dom.randint(0,10)
# What you care about
class SecretGame(object):
def __init__(self, number_generator):
number = number_generator.generate()
print number
Here, none of the classes implement an interface. Python does not care about that, because the SecretGame class will just t...
Sort hash by key, return hash in Ruby
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In Ruby 2.1 it is simple:
h.sort.to_h
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Android Gallery on Android 4.4 (KitKat) returns different URI for Intent.ACTION_GET_CONTENT
Before KitKat (or before the new Gallery) the Intent.ACTION_GET_CONTENT returned a URI like this
19 Answers
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