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Reorder levels of a factor without changing order of values
...f <- data.frame(f = 1:4, g = letters[1:4])
df
# f g
# 1 1 a
# 2 2 b
# 3 3 c
# 4 4 d
levels(df$g)
# [1] "a" "b" "c" "d"
df$g <- factor(df$g, levels = letters[4:1])
# levels(df$g)
# [1] "d" "c" "b" "a"
df
# f g
# 1 1 a
# 2 2 b
# 3 3 c
# 4 4 d
...
map function for objects (instead of arrays)
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38 Answers
38
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Get a random boolean in python?
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349
Adam's answer is quite fast, but I found that random.getrandbits(1) to be quite a lot faster. ...
How do I detect the Python version at runtime? [duplicate]
I have a Python file which might have to support Python versions < 3.x and >= 3.x. Is there a way to introspect the Python runtime to know the version which it is running (for example, 2.6 or 3.2.x )?
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Detect and exclude outliers in Pandas data frame
...ression would do that in one shot.
df = pd.DataFrame(np.random.randn(100, 3))
from scipy import stats
df[(np.abs(stats.zscore(df)) < 3).all(axis=1)]
description:
For each column, first it computes the Z-score of each value in the
column, relative to the column mean and standard deviation.
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Element-wise addition of 2 lists?
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371
Use map with operator.add:
>>> from operator import add
>>> list( map(add, ...
Most popular screen sizes/resolutions on Android phones [closed]
...king for.
– dfetter88
Jun 7 '11 at 23:07
21
That link says nothing of how common a resolution is....
How can I format a decimal to always show 2 decimal places?
...s Decimal('0.01')
>>> # Round to two places
>>> Decimal('3.214').quantize(TWOPLACES)
Decimal('3.21')
>>> # Validate that a number does not exceed two places
>>> Decimal('3.21').quantize(TWOPLACES, context=Context(traps=[Inexact]))
Decimal('3.21')
>>> Deci...
Evenly space multiple views within a container view
...at it worked.
Duh 2: The 'spacer views' could have been transparent.
Duh 3: This approach could be applied horizontally.
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PHP: merge two arrays while keeping keys instead of reindexing?
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You can simply 'add' the arrays:
>> $a = array(1, 2, 3);
array (
0 => 1,
1 => 2,
2 => 3,
)
>> $b = array("a" => 1, "b" => 2, "c" => 3)
array (
'a' => 1,
'b' => 2,
'c' => 3,
)
>> $a + $b
array (
0 => 1,
1 => 2,
2 =&g...