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What is “point free” style (in Functional Programming)?
...you specify the arguments explicitly):
sum (x:xs) = x + (sum xs)
sum [] = 0
Point-free (sum doesn't have any explicit arguments - it's just a fold with + starting with 0):
sum = foldr (+) 0
Or even simpler: Instead of g(x) = f(x), you could just write g = f.
So yes: It's closely related to c...
How do I check in SQLite whether a table exists?
...
1045
I missed that FAQ entry.
Anyway, for future reference, the complete query is:
SELECT name FR...
Returning value from called function in a shell script
... echo >&2 "successfully acquired lock: $lockdir"
retval=0
else
echo >&2 "cannot acquire lock, giving up on $lockdir"
retval=1
fi
return "$retval"
}
testlock
retval=$?
if [ "$retval" == 0 ]
then
echo "directory not created"
else
echo ...
Calculate last day of month in JavaScript
If you provide 0 as the dayValue in Date.setFullYear you get the last day of the previous month:
20 Answers
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How to iterate a loop with index and element in Swift
...
Yes. As of Swift 3.0, if you need the index for each element along with its value, you can use the enumerated() method to iterate over the array. It returns a sequence of pairs composed of the index and the value for each item in the array. For...
Javascript regex returning true.. then false.. then true.. etc [duplicate]
...
/^[^-_]([a-z0-9-_]{4,20})[^-_]$/gi;
You're using a g (global) RegExp. In JavaScript, global regexen have state: you call them (with exec, test etc.) the first time, you get the first match in a given string. Call them again and you get...
Gradient borders
...webkit-border-image: -webkit-gradient(linear, left top, left bottom, from(#00abeb), to(#fff), color-stop(0.5, #fff), color-stop(0.5, #66cc00)) 21 30 30 21 repeat repeat;
Prooflink -- http://www.webkit.org/blog/1424/css3-gradients/
Browser support: http://caniuse.com/#search=border-image
...
How to use shared memory with Linux in C
...lains their purpose.
return mmap(NULL, size, protection, visibility, -1, 0);
}
The following is an example program that uses the function defined above to allocate a buffer. The parent process will write a message, fork, and then wait for its child to modify the buffer. Both processes can read a...
Change URL parameters
...ed Sujoy's code to make up a function.
/**
* http://stackoverflow.com/a/10997390/11236
*/
function updateURLParameter(url, param, paramVal){
var newAdditionalURL = "";
var tempArray = url.split("?");
var baseURL = tempArray[0];
var additionalURL = tempArray[1];
var temp = "";
...
How do I detect the Python version at runtime? [duplicate]
...check that you are running Python 3.x, use
import sys
if sys.version_info[0] < 3:
raise Exception("Must be using Python 3")
Here, sys.version_info[0] is the major version number. sys.version_info[1] would give you the minor version number.
In Python 2.7 and later, the components of sys.ve...