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What does the KEY keyword mean?
...t that constraint. In practice, if you have a FK for example KEY key_name (user_id), CONSTRAINT foreign_key_constraint_name FOREIGN KEY (user_id) REFERENCES auth_user (id) then you might additionally want to specify what INDEX is used (HASH vs BTREE). This example shows KEY and INDEX aren't synonyms...
Read first N lines of a file in python
...hon 2
with open("datafile") as myfile:
head = [next(myfile) for x in xrange(N)]
print head
Python 3
with open("datafile") as myfile:
head = [next(myfile) for x in range(N)]
print(head)
Here's another way (both Python 2 & 3)
from itertools import islice
with open("datafile") as myf...
AngularJS - How to use $routeParams in generating the templateUrl?
...r.
when('/', {templateUrl:'/home'}).
when('/users/:user_id',
{
controller:UserView,
templateUrl: function(params){ return '/users/view/' + params.user_id; }
}
).
otherwise({re...
Warning: Null value is eliminated by an aggregate or other SET operation in Aqua Data Studio
...ULL(
(select count(closed) from ticket
where assigned_to = c.user_id and closed is not null
group by assigned_to), 0),
opencases = ISNULL(
(select count(closed) from ticket
where assigned_to = c.user_id and closed is null
group by assigned_to), 0),
...
Is it a good practice to use try-except-else in Python?
...ample which illustrate everything about try-except-else-finally:
for i in range(3):
try:
y = 1 / i
except ZeroDivisionError:
print(f"\ti = {i}")
print("\tError report: ZeroDivisionError")
else:
print(f"\ti = {i}")
print(f"\tNo error report and y e...
How do I convert a String object into a Hash object?
...ft with an array of hashes which I then merge together.
EXAMPLE INPUT: "{:user_id=>11, :blog_id=>2, :comment_id=>1}"
RESULT OUTPUT: {"user_id"=>"11", "blog_id"=>"2", "comment_id"=>"1"}
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MYSQL OR vs IN performance
...iginal test, as it was 6 years ago, though it returns a result in the same range as this test)
In request for some sample code to test this, here is the simplest possible use case. Using Eloquent for syntax simplicity, raw SQL equivalent executes the same.
$t = microtime(true);
for($i=0; $i<10...
Rolling or sliding window iterator?
...ow(seq, n=2):
it = iter(seq)
win = deque((next(it, None) for _ in xrange(n)), maxlen=n)
yield win
append = win.append
for e in it:
append(e)
yield win
In my tests it handily beats everything else posted here most of the time, though pillmuncher's tee version bea...
How to use a variable to specify column name in ggplot
...> [[1]]
#>
#> [[2]]
# combine all plots
library(egg)
ggarrange(plots = plot_list,
nrow = 2,
labels = c('A)', 'B)'))
Created on 2019-04-04 by the reprex package (v0.2.1.9000)
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Printing without newline (print 'a',) prints a space, how to remove?
... string you're concatenating so this will be fast.
>>> for i in xrange(20):
... s += 'a'
...
>>> print s
aaaaaaaaaaaaaaaaaaaa
Or you can do it more directly using sys.stdout.write(), which print is a wrapper around. This will write only the raw string you give it, without a...