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knife.lazy.mathknife — Lazier evaluated mathing knife

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knife.lazy.mathknife — Lazier evaluated mathing knife

class knife.lazy.mathknife(*things, **kw)

Lazier evaluated mathing knife. Provides numeric and statistical operations for incoming things.

>>> from knife.lazy import mathknife
__init__(*things, snapshots=5)
Parameters:
  • things – incoming things
  • snapshots (integer) – snapshots to keep (default: 5)
__len__()

Number of incoming things.

__iter__()

Iterate over outgoing things.

append(*things)

Insert things after other incoming things.

Parameters:things – incoming things
Return type:knife object
>>> from knife import __
>>> __(3, 4, 5).append(1, 2, 3, 4, 5, 6).peek()
[3, 4, 5, 1, 2, 3, 4, 5, 6]
apply(worker, *args, **kw)

Assign callable used to work on incoming things plus any positional arguments and keyword arguments it will use.

Note

Global positional arguments and keyword arguments assigned with params are reset whenever apply is called.

Parameters:worker – a callable
Return type:knife object
ascii(errors='strict')

encode outgoing things as bytes with the 'latin-1' codec.

Parameters:errors (str) – error handling for encoding
Return type:knife object
>>> from stuf.six import u, b
>>> test = __([1], True, r't', b('i'), u('g'), None, (1,))
>>> test.ascii().oneach().peek()
['[1]', 'True', 't', 'i', 'g', 'None', '(1,)']
average()

Discover average value among incoming things.

Returns:a number
Return type:knife object
>>> from knife import __
>>> __(10, 40, 45).average().get()
31.666666666666668
back()

Switch back to knife object that piped its incoming things through this knife object.

Return type:knife object
baseline()

Restore incoming things back to the baseline snapshot.

Return type:knife object
>>> from knife import __
>>> undone = __(1, 2, 3).prepend(1, 2, 3, 4, 5, 6)
>>> undone.peek()
[1, 2, 3, 4, 5, 6, 1, 2, 3]
>>> undone.snapshot().append(1).append(2).peek()
[1, 2, 3, 4, 5, 6, 1, 2, 3, 1, 2]
>>> undone.baseline().peek()
[1, 2, 3, 4, 5, 6, 1, 2, 3]
bytes(encoding='utf_8', errors='strict')

encode outgoing things as bytes.

Parameters:
Return type:

knife object

>>> test = __([1], True, r't', b('i'), u('g'), None, (1,))
>>> test.bytes().oneach().peek()
['[1]', 'True', 't', 'i', 'g', 'None', '(1,)']
clear()

Clear everything.

Return type:knife object
count()

Discover how common each incoming thing is and the overall count of each incoming thing.

Returns:Collects namedtuple Count(least=int, most=int, overall=[(thing1, int), (thing2, int), ...])
Return type:knife object
>>> common = __(11, 3, 5, 11, 7, 3, 5, 11).count().get()
>>> # least common thing
>>> common.least
7
>>> # most common thing
>>> common.most
11
>>> # total count for every thing
>>> common.overall
[(11, 3), (3, 2), (5, 2), (7, 1)]
get()

Return outgoing things wrapped with wrap.

Note

With only one outgoing thing, only that one outgoing thing is returned. With multiple outgoing things, they are returned wrapped with the wrapper assigned with wrap (default wrapper is list).

max()

Discover the maximum value among incoming things using worker as the key function.

Return type:knife object
>>> # default behavior
>>> __(1, 2, 4).max().get()
4
>>> stooges = (
...    {'name': 'moe', 'age': 40},
...    {'name': 'larry', 'age': 50},
...    {'name': 'curly', 'age': 60},
... )
>>> # using worker as key function
>>> __(*stooges).worker(lambda x: x['age']).max().get()
{'age': 60, 'name': 'curly'}

See also

max
function in Python standard library
max
function in Underscore.js
max
function in Underscore.lua
max
function in Underscore.perl
max
function in Underscore.php
median()

Discover the median value among incoming things.

Returns:a number
Return type:knife object
>>> __(4, 5, 7, 2, 1).median().get()
4
>>> __(4, 5, 7, 2, 1, 8).median().get()
4.5
min()

Discover the minimum value among incoming things using worker as the key function.

Return type:knife object
>>> test = __(10, 5, 100, 2, 1000)
>>> test.min().get()
2
>>> test.original().worker(lambda x: x % 100 == 0).min().get()
10

See also

min
function in Python standard library
min
function in Underscore.js
min
function in Underscore.lua
min
function in Underscore.perl
min
function in Underscore.php
minmax()

Discover the minimum and maximum values among incoming things.

Returns:namedtuple MinMAx(min=value, max=value).
Return type:knife object
>>> minmax = __(1, 2, 4).minmax().get()
>>> minmax.min
1
>>> minmax.max
4
oneach()

Toggle whether each outgoing thing should be individually wrapped with the wrapper assigned with wrap (default wrapper is list ) or whether all outgoing things should be wrapped all at once.

Note

knife object default behavior is to wrap all outgoing things all at once. knife objects reset back to this behavior after get or peek is called.

Return type:knife object
original()

Restore incoming things back to the original snapshot.

Note

THe original snapshot of incoming things is taken following the first knife method call but before the second knife method call (if there is a second method call)

Return type:knife object
>>> undone = __(1, 2, 3).prepend(1, 2, 3, 4, 5, 6)
>>> undone.peek()
[1, 2, 3, 4, 5, 6, 1, 2, 3]
>>> undone.original().peek()
[1, 2, 3]
params(*args, **kw)

Assign positional arguments and keyword arguments to be used globally.

Return type:knife object
pattern(pattern, type='parse', flags=0)

Compile search pattern for use as worker.

Note

Global positional arguments and keyword arguments assigned with params are reset whenever a new pattern is compiled.

Parameters:
Return type:

knife object

>>> # using parse expression
>>> test = __('first test', 'second test', 'third test')
>>> test.pattern('first {}').filter().get()
'first test'
>>> # using glob pattern
>>> test.original().pattern('second*', type='glob').filter().get()
'second test'
>>> # using regular expression
>>> test.original().pattern('third .', type='regex').filter().get()
'third test'
peek()

Preview current incoming things wrapped with wrap.

Note

With only one outgoing thing, only that one thing is returned. With multiple outgoing things, everything is returned wrapped with the wrapper assigned with wrap (default wrapper is list).

pipe(knife)

Pipe incoming things from some other knife object through this knife object.

Parameters:knife – another knife object
Return type:knife object
prepend(*things)

Insert things before other incoming things.

Parameters:things – incoming things
Return type:knife object
>>> __(3, 4, 5).prepend(1, 2, 3, 4, 5, 6).peek()
[1, 2, 3, 4, 5, 6, 3, 4, 5]
range()

Discover the length of the smallest interval that can contain the value of every incoming thing.

Returns:a number
Return type:knife object
>>> __(3, 5, 7, 3, 11).range().get()
8
snapshot()

Take a baseline snapshot of current incoming things.

Return type:knife object
sum(start=0, precision=False)

Discover the total value of adding start and incoming things together.

Parameters:
  • start (int or float) – starting number
  • precision (bool) – add floats with extended precision
Return type:

knife object

>>> # default behavior
>>> __(1, 2, 3).sum().get()
6
>>> # with a starting mumber
>>> __(1, 2, 3).sum(start=1).get()
7
>>> # add floating points with extended precision
>>> __(.1, .1, .1, .1, .1, .1, .1, .1).sum(precision=True).get()
0.8

See also

sum
function in Python standard library
undo(snapshot=0)

Revert incoming things to a previous snapshot.

Note

A snapshot of current incoming things is taken when a knife method is called but before the main body of the method executes.

Parameters:snapshot (int) – number of steps ago 1, 2, 3, etc.
Return type:knife object
>>> undone = __(1, 2, 3).prepend(1, 2, 3, 4, 5, 6)
>>> undone.peek()
[1, 2, 3, 4, 5, 6, 1, 2, 3]
>>> # undo back one step
>>> undone.append(1).undo().peek()
[1, 2, 3, 4, 5, 6, 1, 2, 3]
>>> # undo back one step
>>> undone.append(1).append(2).undo().peek()
[1, 2, 3, 4, 5, 6, 1, 2, 3, 1]
>>> # undo back 2 steps
>>> undone.append(1).append(2).undo(2).peek()
[1, 2, 3, 4, 5, 6, 1, 2, 3, 1]
unicode(encoding='utf_8', errors='strict')

unicode (str under Python 3) decode outgoing things.

Parameters:
Return type:

knife object

>>> test = __([1], True, r't', b('i'), u('g'), None, (1,))
>>> test.unicode().oneach().peek()
[u'[1]', u'True', u't', u'i', u'g', u'None', u'(1,)']
worker(worker)

Assign callable used to work on incoming things.

Note

Global positional arguments and keyword arguments assigned with params are reset whenever a new worker is assigned.

Parameters:worker – a callable
Return type:knife object
wrap(wrapper)

Assign object, type, or class used to wrap outgoing things.

Note

A knife object resets back to its default wrapper (list) after get or peek is called.

Parameters:wrapper – an object, type, or class
Return type:knife object
>>> __(1, 2, 3, 4, 5, 6).wrap(tuple).peek()
(1, 2, 3, 4, 5, 6)

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