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How to toggle a value in Python
...re boolean, the fastest approach is to use the not operator:
>>> x = True
>>> x = not x # toggle
>>> x
False
>>> x = not x # toggle
>>> x
True
>>> x = not x # toggle
>>> x
False
Solution using subtraction
If the ...
When should I use cross apply over inner join?
...
Can anyone give me a good example of when CROSS APPLY makes a difference in those cases where INNER JOIN will work as well?
See the article in my blog for detailed performance comparison:
INNER JOIN vs. CROSS APPLY
CROSS APPLY works better on thi...
Access lapply index names inside FUN
Is there a way to get the list index name in my lapply() function?
12 Answers
12
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Python `if x is not None` or `if not x is None`?
I've always thought of the if not x is None version to be more clear, but Google's style guide and PEP-8 both use if x is not None . Is there any minor performance difference (I'm assuming not), and is there any case where one really doesn't fit (making the other a clear winner for my convent...
How to add a browser tab icon (favicon) for a website?
...ing code to the <head> element:
<link rel="icon" href="http://example.com/favicon.png">
PNG favicons are supported by most browsers, except IE <= 10. For backwards compatibility, you can use ICO favicons.
Note that you don't have to precede icon in rel attribute with shortcut an...
How to generate a range of numbers between two numbers?
I have two numbers as input from the user, like for example 1000 and 1050 .
28 Answers
...
How does the @property decorator work in Python?
...pecial descriptor object:
>>> property()
<property object at 0x10ff07940>
It is this object that has extra methods:
>>> property().getter
<built-in method getter of property object at 0x10ff07998>
>>> property().setter
<built-in method setter of property...
Python nonlocal statement
...
Compare this, without using nonlocal:
x = 0
def outer():
x = 1
def inner():
x = 2
print("inner:", x)
inner()
print("outer:", x)
outer()
print("global:", x)
# inner: 2
# outer: 1
# global: 0
To this, using nonlocal, where inner...
How is a CRC32 checksum calculated?
...eing it, but CRC32 seems either needlessly complicated, or insufficiently explained anywhere I could find on the web.
7 Ans...
Removing nan values from an array
...
If you're using numpy for your arrays, you can also use
x = x[numpy.logical_not(numpy.isnan(x))]
Equivalently
x = x[~numpy.isnan(x)]
[Thanks to chbrown for the added shorthand]
Explanation
The inner function, numpy.isnan returns a boolean/logical array which has the value...