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What's the point of 'const' in the Haskell Prelude?
..., no matter the second, you can do:
listOfNothings :: String -> [Maybe Char]
listOfNothings = (map . const) Nothing
or, more explicitly:
listOfNothing st = map (const Nothing) st
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WPF ListView turn off selection
...
Per Martin Konicek's comment, to fully disable the selection of the items in the simplest manner:
<ListView>
<ListView.ItemContainerStyle>
<Style TargetType="ListViewItem">
<Setter Property="Focusable" Value="false"/>
&...
How to get distinct values for non-key column fields in Laravel?
...lder you can do it this way:
$users = DB::table('users')
->select('id','name', 'email')
->groupBy('name')
->get();
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How to repeat a string a variable number of times in C++?
...ng in C++. Is there any direct way to do this using either std::strings or char* strings?
8 Answers
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How to bind inverse boolean properties in WPF?
... which is easily missed when it (as is often the case) is embedded next to chars that look like it (i.e. one/more "("'s and "l"'s and "I"'s).
– Tom
Jan 18 '18 at 1:54
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Get query string parameters url values with jQuery / Javascript (querystring)
... = key.replace(/[*+?^$.\[\]{}()|\\\/]/g, "\\$&"); // escape RegEx meta chars
var match = location.search.match(new RegExp("[?&]"+key+"=([^&]+)(&|$)"));
return match && decodeURIComponent(match[1].replace(/\+/g, " "));
}
http://jsfiddle.net/gilly3/sgxcL/
An alternat...
How do I find numeric columns in Pandas?
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You could use select_dtypes method of DataFrame. It includes two parameters include and exclude. So isNumeric would look like:
numerics = ['int16', 'int32', 'int64', 'float16', 'float32', 'float64']
newdf = df.select_dtypes(include=numer...
What's the difference between KeyDown and KeyPress in .NET?
...ctical difference between KeyDown and KeyPress is that KeyPress relays the character resulting from a keypress, and is only called if there is one.
In other words, if you press A on your keyboard, you'll get this sequence of events:
KeyDown: KeyCode=Keys.A, KeyData=Keys.A, Modifiers=Keys.None
Key...
Can someone explain collection_select to me in clear, simple terms?
I am going through the Rails API docs for collection_select and they are god-awful.
2 Answers
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MySQL “NOT IN” query
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To use IN, you must have a set, use this syntax instead:
SELECT * FROM Table1 WHERE Table1.principal NOT IN (SELECT principal FROM table2)
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