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Extracting numbers from vectors of strings
...meric(gsub("([0-9]+).*$", "\\1", years))
or
# pattern is to just remove _years_old
as.numeric(gsub(" years old", "", years))
or
# split by space, get the element in first index
as.numeric(sapply(strsplit(years, " "), "[[", 1))
...
find() with nil when there are no records
...
Yes, just do:
Challenge.find_by_id(10)
For Rails 4 and 5:
Challenge.find_by(id: 10)
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How does having a dynamic variable affect performance?
...Generator();
if (!method.IsStatic)
{
il.Emit(OpCodes.Ldarg_0);
il.Emit(OpCodes.Unbox_Any, method.DeclaringType);
}
var parameters = method.GetParameters();
for (int i = 0; i < parameters.Length; i++)
{
il.Emit(OpCodes.Ldarg_1);
il.Emit(OpCo...
DateTime.ToString() format that can be used in a filename or extension?
...our file name.
Here i have provided example
string fileName = "fileName_" + DateTime.Now.ToString("MM-dd-yyyy_hh-mm-ss-tt") + ".pdf";
OR
If you don't prefer to use symbols you can try this also.,
string fileName = "fileName_" + DateTime.Now.ToString("MMddyyyyhhmmsstt") + ".pdf";
Hope this ...
fatal error: malformed or corrupted AST file - Xcode
... Thanks man, this worked. But can you please explain what is all this about_ I like to know why something happens, when it does. And I just had this error when I opened my project the next day, out of the blue.
– SteBra
Jul 23 '14 at 8:27
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How do I generate random numbers in Dart?
...0.9 ... the result would be for example -0.32
– just_a_dude
Nov 7 '13 at 13:59
2
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What is the difference between a definition and a declaration?
...declares foo
}
... or is a typedef or using statement.
typedef long LONG_32; // declares LONG_32
using namespace std; // declares std
Now for the big reason why it's important to understand the difference between a declaration and definition: the One Definition Rule. From section 3.2.1 of t...
Why does the order in which libraries are linked sometimes cause errors in GCC?
...before one another: -la -lb -la.
Linking to dynamic libraries
$ export LD_LIBRARY_PATH=. # not needed if libs go to /usr/lib etc
$ g++ -fpic -shared d.cpp -o libd.so
$ g++ -fpic -shared b.cpp -L. -ld -o libb.so # specifies its dependency!
$ g++ -L. -lb a.cpp # wrong order (works on some distribut...
How do you check whether a number is divisible by another number (Python)?
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@Chris_Rands Put that into an answer, people who do code-golf (like me) would be very happy. In fact, I came here looking for a golfed answer like that.
– MilkyWay90
Nov 11 '18 at 22:29
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What are all the escape characters?
...
\a does not compile in javac 1.8.0_20: illegal escape character: String test = "\a";
– Ehryk
Mar 15 '15 at 18:18
3
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