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Primary key or Unique index?
...ork we have a big database with unique indexes instead of primary keys and all works fine.
15 Answers
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Wildcards in jQuery selectors
I'm trying to use a wildcard to get the id of all the elements whose id begin with "jander". I tried $('#jander*') , $('#jander%') but it doesn't work..
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In c# is there a method to find the max of 3 numbers?
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Well, you can just call it twice:
int max3 = Math.Max(x, Math.Max(y, z));
If you find yourself doing this a lot, you could always write your own helper method... I would be happy enough seeing this in my code base once, but not regularly.
(N...
Combine two ActiveRecord::Relation objects
...lation.or(last_name_relation)
† Only in ActiveRecord 5+; for 4.2 install the where-or backport.
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Single Line Nested For Loops
...ertools.product, which returns an iterable yielding tuples of values from all the iterables you pass it. That is, itertools.product(A, B) yields all values of the form (a, b), where the a values come from A and the b values come from B. For example:
import itertools
A = [50, 60, 70]
B = [0.1, 0.2...
Wait for page load in Selenium
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does this really work all the time? Maybe Im missing something from your code but you are waiting for the dom to be in ready state. But consider that if your code executes too fast the previous page might not be unloaded yet and it will ...
How to execute a raw update sql with dynamic binding in rails
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It doesn't look like the Rails API exposes methods to do this generically. You could try accessing the underlying connection and using it's methods, e.g. for MySQL:
st = ActiveRecord::Base.connection.raw_connection.prepare("update table set f1=? where f2=? and f3=?")
st.execute(f1, f2, f3)
st...
Extract a regular expression match
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Use the new stringr package which wraps all the existing regular expression operates in a consistent syntax and adds a few that are missing:
library(stringr)
str_locate("aaa12xxx", "[0-9]+")
# start end
# [1,] 4 5
str_extract("aaa12xxx", "[0-9]+")
# [1]...
Concurrent vs serial queues in GCD
...ou wouldn't use either of the last two for long running processes. You normally see it when you're trying to update the UI (always on the main thread) from something that may be running on another thread.
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How to determine whether a Pandas Column contains a particular value
...s)
Out[24]: True
As pointed out by @DSM, it may be more efficient (especially if you're just doing this for one value) to just use in directly on the values:
In [31]: s.values
Out[31]: array(['a', 'b', 'c'], dtype=object)
In [32]: 'a' in s.values
Out[32]: True
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