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Why are side-effects modeled as monads in Haskell?
...tion has side effects. If we take all the effects it produces as the input and output parameters, then the function is pure to the outside world.
So, for an impure function
f' :: Int -> Int
we add the RealWorld to the consideration
f :: Int -> RealWorld -> (Int, RealWorld)
-- input some st...
how to exclude null values in array_agg like in string_agg using postgres?
... non_canonical_users
FROM groups g
GROUP BY g.id
) s
Or, simpler and may be cheaper, using array_to_string which eliminates nulls:
SELECT
g.id,
array_to_string(
array_agg(CASE WHEN g.canonical = 'Y' THEN g.users ELSE NULL END)
, ','
) canonical_users,
array...
How to convert the background to transparent? [closed]
...gging the image around in your browser for visibility,
the gray background and the border is not part of the image]
File menu/Save Image
GIF/PNG/ICO image file formats support transparency, JPG doesn't!
share
|
...
Select all columns except one in MySQL?
...,', '') FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_NAME = '<table>' AND TABLE_SCHEMA = '<database>'), ' FROM <table>');
PREPARE stmt1 FROM @sql;
EXECUTE stmt1;
Replacing <table>, <database> and <columns_to_omit>
...
jQuery - Detect value change on hidden input field
...is really change or not. if ($('#userid').val() != myVaule) { // set val() and trigger change }
– nnattawat
Nov 19 '15 at 0:37
...
Loading and parsing a JSON file with multiple JSON objects
I am trying to load and parse a JSON file in Python . But I'm stuck trying to load the file:
3 Answers
...
python: how to send mail with TO, CC and BCC?
...esting purposes to populate few hundred email boxes with various messages, and was going to use smtplib for that. But among other things I need to be able to send messages not only TO specific mailboxes, but CC and BCC them as well. It does not look like smtplib supports CC-ing and BCC-ing while...
Create numpy matrix filled with NaNs
...oops for vector operations in numpy.
You can create an uninitialized array and assign to all entries at once:
>>> a = numpy.empty((3,3,))
>>> a[:] = numpy.nan
>>> a
array([[ NaN, NaN, NaN],
[ NaN, NaN, NaN],
[ NaN, NaN, NaN]])
I have timed the alte...
iOS 7 - Status bar overlaps the view
...In the storyboard, I moved my views 20 pixels down to look right on iOS 7 and in order to make it iOS 6 compatible, I changed Delta y to -20.
Since my storyboard is not using auto-layout, in order to resize the height of views properly on iOS 6 I had to set Delta height as well as Delta Y.
...
Uint8Array to string in Javascript
...
TextEncoder and TextDecoder from the Encoding standard, which is polyfilled by the stringencoding library, converts between strings and ArrayBuffers:
var uint8array = new TextEncoder("utf-8").encode("¢");
var string = new TextDecoder("...