`knife.lazy.cmpknife` — Lazier evaluated comparing knife¶

class knife.lazy.cmpknife(*things, **kw)¶

Lazier evaluated comparing knife. Provides comparison operations for incoming things.

>>> from knife.lazy import cmpknife

__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.

all()¶

Discover if worker is True for all incoming things.

Returns:	`bool`
Return type:	`knife` object

>>> from knife import __
>>> __(2, 4, 6, 8).worker(lambda x: x % 2 == 0).all().get()
True

See also

all: function in Python standard library
all: function in Underscore.js
all: function in Underscore.lua
all: function in Underscore.perl
all: function in Underscore.php

any()¶

Discover if worker is True for any incoming thing.

Returns:	`bool`
Return type:	`knife` object

>>> __(1, 4, 5, 9).worker(lambda x: x % 2 == 0).any().get()
True

See also

any: function in Python standard library
any: function in Underscore.js
any: function in Underscore.lua
any: function in Underscore.perl
any: function in Underscore.php

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,)']

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:	encoding (str) – character encoding errors (str) – error handling for encoding
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

difference(symmetric=False)¶

Discover difference within a series of iterable incoming things.

Parameters:	symmetric (bool) – return symmetric difference
Returns:	`list`
Return type:	`knife` object

>>> # default behavior
>>> test = __([1, 2, 3, 4, 5], [5, 2, 10], [10, 11, 2])
>>> test.difference().get()
[1, 3, 4]
>>> # symmetric difference
>>> test.original().difference(symmetric=True).get()
[1, 2, 3, 4, 11]

See also

set.difference: function in Python standard library
set.symmetric_difference: function in Python standard library
difference: function in Underscore.js
difference: function in Underscore.perl
difference: function in Underscore.php

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).

intersection()¶

Discover intersection within a series of iterable incoming things.

Returns:	`list`
Return type:	`knife` object

>>> __([1, 2, 3], [101, 2, 1, 10], [2, 1]).intersection().get()
[1, 2]

See also

set.intersection: function in Python standard library
intersection: function in Underscore.js
intersection: function in Underscore.perl
intersection: function in Underscore.php

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:	pattern (str) – search pattern type (str) – engine to compile pattern with. Valid options are ‘parse’, ‘re’, or ‘glob’ flags (int) – regular expression flags
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]

snapshot()¶

Take a baseline snapshot of current incoming things.

Return type:	`knife` object

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:	encoding (str) – Unicode encoding errors (str) – error handling for decoding
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,)']

union()¶

Discover union within a series of iterable incoming things.

Returns:	`list`
Return type:	`knife` object

>>> __([1, 2, 3], [101, 2, 1, 10], [2, 1]).union().get()
[1, 10, 3, 2, 101]

See also

set.union: function in Python standard library
union: function in Underscore.js
union: function in Underscore.perl
union: function in Underscore.php

unique()¶

Discover unique incoming things.

Return type:	`knife` object

>>> # default behavior
>>> __(1, 2, 1, 3, 1, 4).unique().get()
[1, 2, 3, 4]
>>> # using worker as key function
>>> __(1, 2, 1, 3, 1, 4).worker(round).unique().get()
[1.0, 2.0, 3.0, 4.0]

See also

uniq: function in Underscore.js
uniq: function in Underscore.perl
uniq: function in Underscore.php

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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