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Null vs. False vs. 0 in PHP
...The var has not been initialized.
False means "not true in a boolean context". Used to explicitly show you are dealing with logical issues.
0 is an int. Nothing to do with the rest above, used for mathematics.
Now, what is tricky, it's that in dynamic languages like PHP, all of them have a value ...
Grouping functions (tapply, by, aggregate) and the *apply family
...rs) that much of the functionality of the *apply family is covered by the extremely popular plyr package, the base functions remain useful and worth knowing.
This answer is intended to act as a sort of signpost for new useRs to help direct them to the correct *apply function for their particular pr...
Element-wise addition of 2 lists?
... list2) )
[5, 7, 9]
or zip with a list comprehension:
>>> [sum(x) for x in zip(list1, list2)]
[5, 7, 9]
Timing comparisons:
>>> list2 = [4, 5, 6]*10**5
>>> list1 = [1, 2, 3]*10**5
>>> %timeit from operator import add;map(add, list1, list2)
10 loops, best of ...
Check if a number is int or float
...
Use isinstance.
>>> x = 12
>>> isinstance(x, int)
True
>>> y = 12.0
>>> isinstance(y, float)
True
So:
>>> if isinstance(x, int):
print 'x is a int!'
x is a int!
_EDIT:_
As pointed out, in case o...
Haskell composition (.) vs F#'s pipe forward operator (|>)
...eralizing let-bindings are sufficiently different as to affect this. For example, I know in F# sometimes writing
let f = exp
will not compile, and you need explicit eta-conversion:
let f x = (exp) x // or x |> exp
to make it compile. This also steers people away from points-free/compos...
Why don't Java's +=, -=, *=, /= compound assignment operators require casting?
Until today, I thought that for example:
11 Answers
11
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Equivalent of Math.Min & Math.Max for Dates?
What's the quickest and easiest way to get the Min (or Max) value between two dates? Is there an equivalent to Math.Min (& Math.Max) for dates?
...
How do I list all files of a directory?
...rt walk
f = []
for (dirpath, dirnames, filenames) in walk(mypath):
f.extend(filenames)
break
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How to change line width in ggplot?
...
Whilst @Didzis has the correct answer, I will expand on a few points
Aesthetics can be set or mapped within a ggplot call.
An aesthetic defined within aes(...) is mapped from the data, and a legend created.
An aesthetic may also be set to a single value, by defining it...
Plotting a list of (x, y) coordinates in python matplotlib
...s (a, b) that I would like to plot with matplotlib in python as actual x-y coordinates. Currently, it is making two plots, where the index of the list gives the x-coordinate, and the first plot's y values are the a s in the pairs and the second plot's y values are the b s in the pairs.
...