yail.core module

yail.core.cycles(seq, n=1)

Cycles through the sequence n-times.

Basically the same as itertools.cycle except that this sets an upper limit on how many cycles will be done.

Note

If n is None, this is identical to itertools.cycle.

Parameters:

• seq (iterable) – The sequence to grab items from.
• n (integral) – Number of times to cycle through.

Returns:

The cycled sequence generator.

Return type:

generator

Examples

>>> list(cycles([1, 2, 3], 2))
[1, 2, 3, 1, 2, 3]

yail.core.disperse(seq)

Similar to range except that it recursively proceeds through the given range in such a way that values that follow each other are preferably not only non-sequential, but fairly different. This does not always work with small ranges, but works nicely with large ranges.

Parameters:

• a (int) – the lower bound of the range
• b (int) – the upper bound of the range

Returns:

a generator that can be used to iterate

through the sequence.

Return type:

result(generator)

Examples

>>> list(disperse(range(10)))
[0, 5, 8, 3, 9, 4, 6, 1, 7, 2]

yail.core.duplicate(seq, n=1)

Gets each element multiple times.

Like itertools.repeat this will repeat each element n-times. However, it will do this for each element of the sequence.

Parameters:

• seq (iterable) – The sequence to grab items from.
• n (integral) – Number of repeats for each element.

Returns:

A generator of repeated elements.

Return type:

generator

Examples

>>> list(duplicate([1, 2, 3], 2))
[1, 1, 2, 2, 3, 3]

yail.core.empty()

Creates an empty iterator.

Examples

>>> list(empty())
[]

yail.core.generator(it)

Creates a generator type from the iterable.

Parameters:it (iterable) – An iterable to make a generator. Returns:A generator made from the iterable. Return type:generator

Examples

>>> generator(range(5))  
<generator object generator at 0x...>

>>> list(generator(range(5)))
[0, 1, 2, 3, 4]

yail.core.indices(*sizes)

Iterates over a length/shape.

Takes a size or sizes (unpacked shape) and iterates through all combinations of the indices.

Parameters:*sizes (int) – list of sizes to iterate over. Returns:an iterator over the sizes. Return type:iterable

Examples

>>> list(indices(3, 2))
[(0, 0), (0, 1), (1, 0), (1, 1), (2, 0), (2, 1)]

yail.core.pad(seq, before=0, after=0, fill=None)

Pads a sequence by a fill value before and/or after.

Pads the sequence before and after using the fill value provided by fill up to the lengths specified by before and after. If either before or after is None, pad the fill value infinitely on the respective end.

Note

If before``is ``None, the sequence will only be the fill value.

Parameters:

• seq (iterable) – Sequence to pad.
• before (integral) – Amount to pad before.
• after (integral) – Amount to pad after.
• fill (any) – Some value to pad with.

Returns:

A sequence that has been padded.

Return type:

iterable

Examples

>>> list(pad(range(2, 4), before=1, after=2, fill=0))
[0, 2, 3, 0, 0]

yail.core.single(val)

Creates an iterator with a single value.

Parameters:val (any) – Single value to add to the iterator. Returns:An iterable yielding the single value. Return type:iterable

Examples

>>> list(single(1))
[1]

yail.core.sliding_window_filled(seq, n, pad_before=False, pad_after=False, fillvalue=None)

A sliding window with optional padding on either end..

Parameters:

• seq (iter) – an iterator or something that can be turned into an iterator
• n (int) – number of generators to create as lagged
• pad_before (bool) – whether to continue zipping along the longest generator
• pad_after (bool) – whether to continue zipping along the longest generator
• fillvalue – value to use to fill generators shorter than the longest.

Returns:

a generator object that will return

values from each iterator.

Return type:

generator object

Examples

>>> list(sliding_window_filled(range(5), 2))
[(0, 1), (1, 2), (2, 3), (3, 4)]

>>> list(sliding_window_filled(range(5), 2, pad_after=True))
[(0, 1), (1, 2), (2, 3), (3, 4), (4, None)]

>>> list(sliding_window_filled(range(5), 2, pad_before=True, pad_after=True))
[(None, 0), (0, 1), (1, 2), (2, 3), (3, 4), (4, None)]

yail.core.split(n, seq)

Splits the sequence around element n.

Provides 3 ``iterable``s in return.

1. Everything before the n-th value.
2. An iterable with just the n-th value.
3. Everything after the n-th value.

Parameters:

• n (integral) – Index to split the iterable at.
• seq (iterable) – The sequence to split.

Returns:

Each portion of the iterable

around the index.

Return type:

tuple of ``iterable``s

Examples

>>> list(map(tuple, split(2, range(5))))
[(0, 1), (2,), (3, 4)]

>>> list(map(tuple, split(2, [10, 20, 30, 40, 50])))
[(10, 20), (30,), (40, 50)]

yail.core.subrange(start, stop=None, step=None, substep=None)

Generates start and stop values for each subrange.

Parameters:

• start (int) – First value in range (or last if only specified value)
• stop (int) – Last value in range
• step (int) – Step between each range
• substep (int) – Step within each range

Yields:

range – A subrange within the larger range.

Examples

>>> list(map(list, subrange(5)))
[[0], [1], [2], [3], [4]]

>>> list(map(list, subrange(0, 12, 3, 2)))
[[0, 2], [3, 5], [6, 8], [9, 11]]