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How do I calculate percentiles with python/numpy?
...centile() is available in numpy too.
import numpy as np
a = np.array([1,2,3,4,5])
p = np.percentile(a, 50) # return 50th percentile, e.g median.
print p
3.0
This ticket leads me to believe they won't be integrating percentile() into numpy anytime soon.
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How do you rotate a two dimensional array?
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63 Answers
63
Active
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How to randomize (or permute) a dataframe rowwise and columnwise?
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234
Given the R data.frame:
> df1
a b c
1 1 1 0
2 1 0 0
3 0 1 0
4 0 0 0
Shuffle row-wise:
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Index all *except* one item in python
...you could use a list comp. For example, to make b a copy of a without the 3rd element:
a = range(10)[::-1] # [9, 8, 7, 6, 5, 4, 3, 2, 1, 0]
b = [x for i,x in enumerate(a) if i!=3] # [9, 8, 7, 5, 4, 3, 2, 1, 0]
This is very general, and can be used with all iterables, incl...
Matplotlib scatter plot with different text at each data point
... could use annotate() while iterating over the values in n.
y = [2.56422, 3.77284, 3.52623, 3.51468, 3.02199]
z = [0.15, 0.3, 0.45, 0.6, 0.75]
n = [58, 651, 393, 203, 123]
fig, ax = plt.subplots()
ax.scatter(z, y)
for i, txt in enumerate(n):
ax.annotate(txt, (z[i], y[i]))
There are a lot of...
Adding new column to existing DataFrame in Python pandas
... a b c d
6 -0.269221 -0.026476 0.997517 1.294385
8 0.917438 0.847941 0.034235 -0.448948
>>> df1['e'] = pd.Series(np.random.randn(sLength), index=df1.index)
>>> df1
a b c d e
6 -0.269221 -0.026476 0.997517 ...
pandas: filter rows of DataFrame with operator chaining
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398
I'm not entirely sure what you want, and your last line of code does not help either, but anyw...
Apply a function to every row of a matrix or a data frame
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You simply use the apply() function:
R> M <- matrix(1:6, nrow=3, byrow=TRUE)
R> M
[,1] [,2]
[1,] 1 2
[2,] 3 4
[3,] 5 6
R> apply(M, 1, function(x) 2*x[1]+x[2])
[1] 4 10 16
R>
This takes a matrix and applies a (silly) function to each row. You pass extr...
Is there a simple way to remove multiple spaces in a string?
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Francisco Couzo
8,04633 gold badges2929 silver badges3737 bronze badges
answered Oct 9 '09 at 21:52
Josh LeeJosh Lee
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Double vs. BigDecimal?
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463
A BigDecimal is an exact way of representing numbers. A Double has a certain precision. Working ...