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Find rows with multiple duplicate fields with Active Record, Rails & Postgres
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I had to pass an explict array to select() as in: User.select([:first,:email]).group(:first,:email).having("count(*) > 1").count in order to work.
– Rafael Oliveira
Oct 6 '14 at 22:27
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How to convert comma-delimited string to list in Python?
...at;dog:greff,snake/
example delimeters: ,;- /|:
'''
def string_to_splitted_array(data,delimeters):
#result list
res = []
# we will add chars into sub_str until
# reach a delimeter
sub_str = ''
for c in data: #iterate over data char by char
# if we reached a delimeter,...
Abort Ajax requests using jQuery
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Save the calls you make in an array, then call xhr.abort() on each.
HUGE CAVEAT: You can abort a request, but that's only the client side. The server side could still be processing the request. If you are using something like PHP or ASP with session data...
What is the use of hashCode in Java?
...eed to store objects will use a hashCode modulo the size of their internal array to choose in what "memory position" (i.e. array position) to store the object.
There are some cases where collisions may occur (two objects end up with the same hashcode), and that, of course, needs to be solved carefu...
In php, is 0 treated as empty?
...as an integer)
0.0 (0 as a float)
"0" (0 as a string)
NULL
FALSE
array() (an empty array)
var $var; (a variable declared, but without a value in a class)
Note that this is exactly the same list as for a coercion to Boolean false. empty is simply !isset($var) || !$var. Try isset inst...
Finding the average of a list
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Oh, but np.array(l).mean() is much faster.
– L. Amber O'Hearn
Sep 23 '15 at 19:16
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binning data in python with scipy/numpy
is there a more efficient way to take an average of an array in prespecified bins? for example, i have an array of numbers and an array corresponding to bin start and end positions in that array, and I want to just take the mean in those bins? I have code that does it below but i am wondering how it...
Collections.emptyList() vs. new instance
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@AJW, yes. But compared to, say, new ArrayList<>() it also makes the design decision clear; elements will not be added to this list.
– aioobe
Apr 28 '19 at 23:54
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How to get a value from a cell of a dataframe?
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You can turn your 1x1 dataframe into a numpy array, then access the first and only value of that array:
val = d2['col_name'].values[0]
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How to loop through all enum values in C#? [duplicate]
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You can cast the array directly: (T[])Enum.GetValues(typeof(T))
– Şafak Gür
Nov 22 '12 at 9:51
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