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Postgres unique constraint vs index
...ead access to the table.
Adding a constraint does put a table lock (so all selects are blocked) since it is added via ALTER TABLE.
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count the frequency that a value occurs in a dataframe column
...iple columns in a df
[my_series[c].value_counts() for c in list(my_series.select_dtypes(include=['O']).columns)]
https://stackoverflow.com/a/28192263/786326
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Proper way to use AJAX Post in jquery to pass model from strongly typed MVC3 view
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EDIT: had to use data: $('input, textarea, select').serialize(), for mine to work.
– TheGeekZn
Jul 30 '13 at 10:37
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How is a tag different from a branch in Git? Which should I use, here?
...;" would generate anonymous unnamed branch (so called 'detached HEAD') and select state of tag. Creating a new commit does it on this unnamed branch, and does not change what tag points to.
– Jakub Narębski
Feb 16 '12 at 14:04
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Why is '397' used for ReSharper GetHashCode override?
...g a hash the result will overflow (since GetHashCode() returns an Int32). Selecting a prime is just helpful for distribution, I don't have a math degree so I'm not going to try and explain it, but multiplication by a prime will have a result that's more well distributed than multiplication by any o...
How do I check if a given Python string is a substring of another one? [duplicate]
...ever you are looking for make a regex-group auto of it, afterwards you can select the 3rd group.
– Cutton Eye
Feb 8 '18 at 15:35
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Apply style to parent if it has child with css [duplicate]
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It's not possible with CSS3. There is a proposed CSS4 selector, $, to do just that, which could look like this (Selecting the li element):
ul $li ul.sub { ... }
See the list of CSS4 Selectors here.
As an alternative, with jQuery, a one-liner you could make use of would be th...
Swift equivalent of [NSBundle bundleForClass:[self class]]
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The selected answer did not work for me in a static method of a UIView subclass, but I found this:
Bundle(for: self.classForCoder)
This also works when you want to get the Bundle within a test target.
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Are nested HTML comments possible?
...ere. Its parent element has to be either the <body> element or a few select others.
– John E
Jan 17 '19 at 14:09
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AddBusinessDays and GetBusinessDays
...using negative numbers with AddBusinessDays allows non-business days to be selected.
– Ristogod
May 28 '14 at 17:37
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