def xchoice(iterable):
'''
Randomly :term:`slice` off **one** items in `iterable`.
:argument iterable: :term:`iterable`
>>> from blade.xslice import xchoice
>>> list(xchoice([1, 2, 3, 4, 5, 6])) # doctest: +SKIP
3
'''
i1, i2 = tee(iterable)
return xat(i1, randrange(0, count(i2)))
def xinitial(iterable):
'''
:term:`Slice` off every items in `iterable` except the **last** `iterable`.
:argument iterable: :term:`iterable`
:return: :term:`iterator` of items
>>> from blade.xslice import xinitial
>>> list(xinitial([5, 4, 3, 2, 1]))
[5, 4, 3, 2]
'''
i1, i2 = tee(iterable)
return islice(i1, count(i2) - 1)
def xaverage(iterable):
'''
Discover average value of numbers in `iterable`.
:argument iterable: iterable object
:return: a number
>>> from blade.xmath import xaverage
>>> xaverage([10, 40, 45])
31.666666666666668
'''
i1, i2 = tee(iterable)
return truediv(sum(i1, 0.0), count(i2))
def xsample(iterable, n):
'''
Randomly :term:`slice` off `n` items in `iterable`.
:argument iterable: :term:`iterable`
:argument int n: sample size
:return: :term:`iterator` of items
>>> from blade.xslice import xsample
>>> list(xsample([1, 2, 3, 4, 5, 6], 3)) # doctest: +SKIP
[2, 4, 5]
'''
i1, i2 = tee(iterable)
return partmap(
lambda i, r, c, x: i(x, r(0, c)),
tee(i2, n),
islice,
randrange,
count(i1),
)
def xmedian(iterable):
'''
Discover median value of numbers in `iterable`.
:argument iterable: iterable object
:return: a number
>>> from blade.xmath import xmedian
>>> xmedian([4, 5, 7, 2, 1])
4
>>> xmedian([4, 5, 7, 2, 1, 8])
4.5
'''
i1, i2 = tee(sorted(iterable))
result = truediv(count(i1) - 1, 2)
pint = int(result)
if result % 2 == 0:
return xslicer(i2, pint)
i3, i4 = tee(i2)
return truediv(xslicer(i3, pint) + xslicer(i4, pint + 1), 2)
def xlast(iterable, n=0):
'''
:term:`Slice` off `n` things from the **tail** end of items in `iterable` or
just the **last** items in `iterable`.
:argument iterable: :term:`iterable`
:keyword int n: number of items in `iterable` to slice off
:return: :term:`iterator` of items
>>> from blade.xslice import xlast
>>> # default behavior
>>> list(xlast([5, 4, 3, 2, 1]))[0]
1
>>> # fetch last two things
>>> list(xlast([5, 4, 3, 2, 1], 2))
[2, 1]
'''
if n:
i1, i2 = tee(iterable)
return islice(i1, count(i2) - n, None)
return iter(deferfunc(deque(iterable, maxlen=1).pop))
def test_count(self):
from stuf.iterable import count
self.assertEqual(count([1, 2, 3]), 3)
