prctile not interpolating

I would like to find percentiles, with interpolation where needed, but the matplotlib prctile seems to be different to matlab in this respect:

In [1]: x = array([ 3.0, 5.0, 7.0, 8.0, 9.0, 11.0 ])

In [2]: median(x)
Out[2]: 7.5

In [3]: prctile(x,50)
Out[3]: 8.0

is there a function available which does include interpolation, or should I just write my own? (I'd also like 10th and 90th percentiles for example).

Thanks, Dave

You can use the scipy version:

~|[10]>from scipy.stats import stats
~|[11]>stats.scoreatpercentile(x,50)

Out [11]:7.5

···

Le vendredi 28 mars 2008, David Simpson a écrit :

I would like to find percentiles, with interpolation where needed, but
the matplotlib prctile seems to be different to matlab in this respect:

In [1]: x = array([ 3.0, 5.0, 7.0, 8.0, 9.0, 11.0 ])

In [2]: median(x)
Out[2]: 7.5

In [3]: prctile(x,50)
Out[3]: 8.0

is there a function available which does include interpolation, or
should I just write my own? (I'd also like 10th and 90th percentiles for
example).

Thanks, Dave

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