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How to play with Control.Monad.Writer in haskell?
... <- logNumber 5; return (a*b) }
:: Writer [String] Int
(Input actually entered all on one line). Here I've specified the type of multWithLog to be Writer [String] Int. Now I can run it:
ghci> runWriter multWithLog
(15, ["Got number: 3","Got number: 5"])
And you see that we log all of ...
What character to use to put an item at the end of an alphabetic list?
...ercase "L" and the Greek alphabet sorts after the Latin alphabet on almost all OS's.
– stupidkid
Sep 9 '16 at 2:54
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What does the “@” symbol do in Powershell?
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PowerShell will actually treat any comma-separated list as an array:
"server1","server2"
So the @ is optional in those cases. However, for associative arrays, the @ is required:
@{"Key"="Value";"Key2"="Value2"}
Officially, @ is the "array ...
What is a semaphore?
...s bouncers at a nightclub. There are a dedicated number of people that are allowed in the club at once. If the club is full no one is allowed to enter, but as soon as one person leaves another person might enter.
It's simply a way to limit the number of consumers for a specific resource. For exampl...
Java - get pixel array from image
... is to be able to address pixel (x, y) from the image using int[x][y] . All the methods I have found do not do this (most of them return int[] s).
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How to format current time using a yyyyMMddHHmmss format?
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acturally the golang format is very strange. why not use the yyyymmddHHiiss style , but use the ""2006/01/02/15/04/05", I have not get it the real reason
– Kewin
May 10 '16 at 14:32
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How can I post data as form data instead of a request payload?
In the code below, the AngularJS $http method calls the URL, and submits the xsrf object as a "Request Payload" (as described in the Chrome debugger network tab). The jQuery $.ajax method does the same call, but submits xsrf as "Form Data".
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Insert line after first match using sed
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Note the standard sed syntax (as in POSIX, so supported by all conforming sed implementations around (GNU, OS/X, BSD, Solaris...)):
sed '/CLIENTSCRIPT=/a\
CLIENTSCRIPT2="hello"' file
Or on one line:
sed -e '/CLIENTSCRIPT=/a\' -e 'CLIENTSCRIPT2="hello"' file
(-expressions (and t...
How to get current path with query string using Capybara
The page url is something like /people?search=name
while I used current_path method of capybara it returned /people only.
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Which characters are valid/invalid in a JSON key name?
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Not those. Whatever needs escaping in JavaScript generally needs it in JSON. Best to get it from the horse's mouth, though, at json.org. It takes about one minute to read the entire spec end-to-end.
– Marcelo Cantos
Dec 30 '11 at 4:21
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