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How can a Java variable be different from itself?
...same with Double.NaN.
From JLS §15.21.1. Numerical Equality Operators == and !=:
Floating-point equality testing is performed in accordance with the rules of the IEEE 754 standard:
If either operand is NaN, then the result of == is false but the result of != is true.
Indeed, the test x!=x is tru...
How to get next/previous record in MySQL?
Say I have records with IDs 3,4,7,9 and I want to be able to go from one to another by navigation via next/previous links. The problem is, that I don't know how to fetch record with nearest higher ID.
...
Displaying a message in iOS which has the same functionality as Toast in Android
...to know if there is any method in iOS which behaves like Toast messages in Android. That is, I need to display a message which is dismissed automatically after few seconds. This is similar to the functionality of the Toast class in the Android environment.
...
Pandas - How to flatten a hierarchical index in columns
...eed.
From panda's own documentation:
MultiIndex.to_flat_index()
Convert a MultiIndex to an Index of Tuples containing the level values.
A simple example from its documentation:
import pandas as pd
print(pd.__version__) # '0.23.4'
index = pd.MultiIndex.from_product(
[['foo', 'ba...
Create PostgreSQL ROLE (user) if it doesn't exist
...catch only this one error. As other answers mentioned it is a good idea to convert fatal error to simple notice. Other PostgreSQL IF NOT EXISTS commands adds , skipping into their message, so for consistency I'm adding it here too.
Here is full SQL code for simulation of CREATE ROLE IF NOT EXISTS w...
“used as value” in function call
... postfix: "",
imageUploader: {
brandingHtml: "Powered by \u003ca href=\"https://imgur.com/\"\u003e\u003csvg class=\"svg-icon\" width=\"50\" height=\"18\" viewBox=\"0 0 50 18\" fill=\"none\" xmlns=\"http://www.w3.org/2000/svg\"\u003e\u003cpath d=\"M46.1709 9....
How is __eq__ handled in Python and in what order?
....x sees a == b, it tries the following.
If type(b) is a new-style class, and type(b) is a subclass of type(a), and type(b) has overridden __eq__, then the result is b.__eq__(a).
If type(a) has overridden __eq__ (that is, type(a).__eq__ isn't object.__eq__), then the result is a.__eq__(b).
If type(...
How to get a list of installed Jenkins plugins with name and version pair
...
Worked well for me on Mac OS X. I wanted to convert the output to a plain text list, so used some Perl regex to strip the tags: curl 'http://192.168.197.133:8080/pluginManager/api/xml?depth=1&xpath=/*/*/shortName|/*/*/version&wrapper=plugins' | perl -pe 's/.*?&...
MySQL offset infinite rows
...d... but no! I've seen this 18446744073709551615 scatter all over the code and I was blaming lazy programmers, but it's a design feature!
– Petruza
May 24 '10 at 15:10
8
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Why does a RegExp with global flag give wrong results?
...'.match(re); // -> true
!!'Foo Bar'.match(re); // -> true
Note: !! converts it to a boolean and then inverts the boolean so it reflects the result.
Alternatively, you could just reset the lastIndex property:
result.push(re.test('Foo Bar'));
re.lastIndex = 0;
result.push(re.test('Foo Bar'))...