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Associativity of “in” in Python?
...
123
1 in [] in 'a' is evaluated as (1 in []) and ([] in 'a').
Since the first condition (1 in [])...
how do I insert a column at a specific column index in pandas?
...e beginning
df.insert(loc, column, value)
df = pd.DataFrame({'B': [1, 2, 3], 'C': [4, 5, 6]})
df
Out:
B C
0 1 4
1 2 5
2 3 6
idx = 0
new_col = [7, 8, 9] # can be a list, a Series, an array or a scalar
df.insert(loc=idx, column='A', value=new_col)
df
Out:
A B C
0 7 1 4
...
Sample random rows in dataframe
...
First make some data:
> df = data.frame(matrix(rnorm(20), nrow=10))
> df
X1 X2
1 0.7091409 -1.4061361
2 -1.1334614 -0.1973846
3 2.3343391 -0.4385071
4 -0.9040278 -0.6593677
5 0.4180331 -1.2592415
6 0.7572246 -0.5463655
7 -0.8996483 0.4231117
8 ...
Difference between numpy.array shape (R, 1) and (R,)
... how to interpret the data buffer.
For example, if we create an array of 12 integers:
>>> a = numpy.arange(12)
>>> a
array([ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11])
Then a consists of a data buffer, arranged something like this:
┌────┬────┬──...
How can I get the intersection, union, and subset of arrays in Ruby?
...union
def |(other)
@set | other.set
end
end
x = MultiSet.new([1,1,2,2,3,4,5,6])
y = MultiSet.new([1,3,5,6])
p x - y # [2,2,4]
p x & y # [1,3,5,6]
p x | y # [1,2,3,4,5,6]
share
|
impro...
Subscripts in plots in R
...to write subscripts in the title or the subtitle in R.
How can I write v 1,2 with 1,2 as subscripts?
6 Answers
...
What does “@@ -1 +1 @@” mean in Git's diff output?
...time
+++ to-file to-file-modification-time
The time stamp looks like 2002-02-21 23:30:39.942229878 -0800 to indicate the date, time with fractional seconds, and time zone. The fractional seconds are omitted on hosts that do not support fractional time stamps.
You can change the header's c...
How can I obtain the element-wise logical NOT of a pandas Series?
...
274
To invert a boolean Series, use ~s:
In [7]: s = pd.Series([True, True, False, True])
In [8]:...
How to download Xcode DMG or XIP file?
...ion (6.3, 5.1, etc.) only the latest revision is kept in the list.)
Xcode 12
12.2 beta
12 (Requires macOS 10.15.4 or later) (Latest as of 17-Sept-2020)
Xcode 11
11.7 (Latest as of Sept 02 2020)
11.6
11.5
11.4.1 (Requires macOS 10.15.2 or later)
11.3.1
11.2.1
11.1
11 (Requires macOS 10.1...
Filtering a list based on a list of booleans
...ss:
>>> from itertools import compress
>>> list_a = [1, 2, 4, 6]
>>> fil = [True, False, True, False]
>>> list(compress(list_a, fil))
[1, 4]
Timing comparisons(py3.x):
>>> list_a = [1, 2, 4, 6]
>>> fil = [True, False, True, False]
>>>...