25 lines
376 B
Python
25 lines
376 B
Python
>>> from math import sqrt
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>>> def sdcreator():
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sum = sum2 = n = 0
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while True:
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x = yield sqrt(sum2/n - sum*sum/n/n) if n else None
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sum += x
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sum2 += x*x
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n += 1.0
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>>> sd = sdcreator()
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>>> sd.send(None)
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>>> for value in (2,4,4,4,5,5,7,9):
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print (value, sd.send(value))
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2 0.0
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4 1.0
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4 0.942809041582
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4 0.866025403784
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5 0.979795897113
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5 1.0
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7 1.39970842445
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9 2.0
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