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What is the Ruby (spaceship) operator?
...ther language that supports it. Basically instead of returning 1 (true) or 0 (false) depending on whether the arguments are equal or unequal, the spaceship operator will return 1, 0, or −1 depending on the value of the left argument relative to the right argument.
a <=> b :=
if a < b t...
Array slicing in Ruby: explanation for illogical behaviour (taken from Rubykoans.com)
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10 Answers
10
Active
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How to filter Pandas dataframe using 'in' and 'not in' like in SQL
...where)
As a worked example:
import pandas as pd
>>> df
country
0 US
1 UK
2 Germany
3 China
>>> countries_to_keep
['UK', 'China']
>>> df.country.isin(countries_to_keep)
0 False
1 True
2 False
3 True
Name: country, dtype: bool
>>>...
How to calculate cumulative normal distribution?
...le:
>>> from scipy.stats import norm
>>> norm.cdf(1.96)
0.9750021048517795
>>> norm.cdf(-1.96)
0.024997895148220435
In other words, approximately 95% of the standard normal interval lies within two standard deviations, centered on a standard mean of zero.
If you need t...
How to check BLAS/LAPACK linkage in NumPy and SciPy?
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edited Dec 16 '19 at 11:30
Demi-Lune
1,22822 gold badges1010 silver badges1919 bronze badges
answered O...
How do you plot bar charts in gnuplot?
...
Simple bar graph:
set boxwidth 0.5
set style fill solid
plot "data.dat" using 1:3:xtic(2) with boxes
data.dat:
0 label 100
1 label2 450
2 "bar label" 75
If you want to style your bars differently, you can do something like:
set style lin...
Pandas percentage of total with groupby
...swer:
# From Paul H
import numpy as np
import pandas as pd
np.random.seed(0)
df = pd.DataFrame({'state': ['CA', 'WA', 'CO', 'AZ'] * 3,
'office_id': list(range(1, 7)) * 2,
'sales': [np.random.randint(100000, 999999)
for _ in range(12...
Why does GCC generate 15-20% faster code if I optimize for size instead of speed?
I first noticed in 2009 that GCC (at least on my projects and on my machines) have the tendency to generate noticeably faster code if I optimize for size ( -Os ) instead of speed ( -O2 or -O3 ), and I have been wondering ever since why.
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How to find all serial devices (ttyS, ttyUSB, ..) on Linux without opening them?
...ystem should contain plenty information for your quest. My system (2.6.32-40-generic #87-Ubuntu) suggests:
/sys/class/tty
Which gives you descriptions of all TTY devices known to the system. A trimmed down example:
# ll /sys/class/tty/ttyUSB*
lrwxrwxrwx 1 root root 0 2012-03-28 20:43 /sys/class/...
How to format numbers by prepending 0 to single-digit numbers?
I want to format a number to have two digits. The problem is caused when 0 – 9 is passed, so I need it to be formatted to 00 – 09 .
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