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What's the idiomatic syntax for prepending to a short python list?
... explanation for the missing list.prepend() . Assuming my list is short and performance concerns are negligible, is
4 A...
Fastest way to determine if an integer's square root is an integer
... ~35% faster than your 6bits+Carmack+sqrt code, at least with my CPU (x86) and programming language (C/C++). Your results may vary, especially because I don't know how the Java factor will play out.
My approach is threefold:
First, filter out obvious answers. This includes negative numbers and ...
What is the best way to filter a Java Collection?
...
Java 8 (2014) solves this problem using streams and lambdas in one line of code:
List<Person> beerDrinkers = persons.stream()
.filter(p -> p.getAge() > 16).collect(Collectors.toList());
Here's a tutorial.
Use Collection#removeIf to modify the collection...
What is the difference between join and merge in Pandas?
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I always use join on indices:
import pandas as pd
left = pd.DataFrame({'key': ['foo', 'bar'], 'val': [1, 2]}).set_index('key')
right = pd.DataFrame({'key': ['foo', 'bar'], 'val': [4, 5]}).set_index('key')
left.join(right, lsuffix='_l', rsuffix='_r')
val_l ...
How do you test that a Python function throws an exception?
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I'm using Python 2.7.10, and the above doesn't work; context.exception does not give the message; it is a type.
– LateCoder
Feb 25 '16 at 16:55
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Hibernate - Batch update returned unexpected row count from update: 0 actual row count: 0 expected:
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Without code and mappings for your transactions, it'll be next to impossible to investigate the problem.
However, to get a better handle as to what causes the problem, try the following:
In your hibernate configuration, set hibernate.s...
Ignore with CSS?
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With css, you can "hide" the br tags and they won't have an effect:
br {
display: none;
}
If you only want to hide some within a specific heading type, just make your css more specific.
h3 br {
display: none;
}
...
Global variables in Java
... public static int a;
public static int b;
}
now you can access a and b from anywhere
by calling
Example.a;
Example.b;
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Update Git submodule to latest commit on origin
I have a project with a Git submodule. It is from an ssh://... URL, and is on commit A. Commit B has been pushed to that URL, and I want the submodule to retrieve the commit, and change to it.
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PostgreSQL function for last inserted ID
...an id column created with the SERIAL pseudo-type. To avoid relying on this and to feel more clean, you can use instead pg_get_serial_sequence:
INSERT INTO persons (lastname,firstname) VALUES ('Smith', 'John');
SELECT currval(pg_get_serial_sequence('persons','id'));
Caveat: currval() only work...