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How to use a variable to specify column name in ggplot
...t will remain around for a long time).
The idiomatic way now would be to convert to a symbol the string that the variable contains, using sym()(which is almost the same as base aliases as.name() / as.symbol()), and unquote it using !!
Simulating OP's data we can do :
library(tidyverse)
rates.by....
Get the length of a String
...0;, Snail 🐌, Penguin 🐧, Dromedary 🐪"
println("unusualMenagerie has \(count(unusualMenagerie)) characters")
// prints "unusualMenagerie has 40 characters"
right from the Apple Swift Guide
(note, for versions of Swift earlier than 1.2, this would be countElements...
How to overload the operator++ in two different ways for postfix a++ and prefix ++a?
...plement postfix in terms of prefix.
//
Number operator++ (int) // postfix ++
{
Number result(*this); // make a copy for result
++(*this); // Now use the prefix version to do the work
return result; // return the copy ...
What is the use of static variable in C#? When to use it? Why can't I declare the static variable in
...
Example without declaring it static:
public class Variable
{
public int i = 5;
public void test()
{
i = i + 5;
Console.WriteLine(i);
}
}
public class Exercise
{
static void Main()
{
Variable var = new Variable();
var.test();
Variab...
Linq list of lists to single list
...
Here is a sample code for you:
List<int> listA = new List<int> { 1, 2, 3, 4, 5, 6 };
List<int> listB = new List<int> { 11, 12, 13, 14, 15, 16 };
List<List<int>> listOfLists = new List<List<int>> { listA, listB };
...
Why NSUserDefaults failed to save NSMutableDictionary in iOS?
...
When I need the data, I read out the NSData, and use NSKeyedUnarchiver to convert NSData back to the object.
It is a little cumbersome, because i need to convert to/from NSData everytime, but it just works.
Here is one example per request:
Save:
NSUserDefaults *defaults = [NSUserDefaults stand...
How to elegantly check if a number is within a range?
...
There are a lot of options:
int x = 30;
if (Enumerable.Range(1,100).Contains(x))
//true
if (x >= 1 && x <= 100)
//true
Also, check out this SO post for regex options.
...
Java String - See if a string contains only numbers and not letters
...ontains only numerics.
If you actually want to use the numeric value, use Integer.parseInt() or Double.parseDouble() as others have explained below.
As a side note, it's generally considered bad practice to compare boolean values to true or false. Just use if (condition) or if (!condition).
...
How does a garbage collector avoid an infinite loop here?
...ion running. The main thread completes effectively right away, at which point the finalizer thread simply runs as many times as it gets a chance to before the process gets torn down. Nothing is keeping the program alive.
s...
What is the C++ function to raise a number to a power?
...e <cmath> header has these overloads:
pow(float, float);
pow(float, int);
pow(double, double); // taken over from C
pow(double, int);
pow(long double, long double);
pow(long double, int);
Now you can't just do
pow(2, N)
with N being an int, because it doesn't know which of float, double...