izy
Python functions and classes that make it even easier! You will wonder why these are not already built-in in python! :)
You can skip README and follow (and run) its equivalent demo notebook.
The sooner you pip install izy
, the less time you waste! Just 3 keystrokes to install and import :)
pip install izy
Now that you have it, here are the functionlities:
Sorting
Some operations like argsort
need 1 or 2 lines to implement in python, but the code is not pythonically readable as it should be. Some other functions like topk
are somehow hidden in the built-in modules, which we expose with ease!
Let us have a big list of numbers and give it an izy
try:
>>> from izy import *
>>> mylist = [4.2, 10, -8, 0, 4, 33, 6, 97, 1, 6., 41, -6, 0.0]
>>> topk(mylist, 4)
[97, 41, 33, 10]
>> topk(mylist, -3) # as you would expect
[-8, -6, 0]
>>> argmax(mylist) # not to mention argmin
7
>>> argsort(mylist)
[2, 11, 3, 12, 8, 4, 0, 6, 9, 1, 5, 10, 7]
>>> argsort(mylist, reverse=True)
[7, 10, 5, 1, 6, 9, 0, 4, 8, 3, 12, 11, 2]
>>> descending(mylist) # I like it more than sorted(x, reverse=True)
[97, 41, 33, 10, 6, 6.0, 4.2, 4, 1, 0, 0.0, -6, -8]
>>> reorder(mylist, argsort(mylist)) # like numpy array indexing
[-8, -6, 0, 0.0, 1, 4, 4.2, 6, 6.0, 10, 33, 41, 97]
If you have a dict
(or more precisely a Mapping
), the arg*
functions take keys
as indices:
>>> mydict = {'a': 1, 'b': 4, 'c': -1}
>>> argmin(mydict)
'c'
>>> reorder(mydict, argsort(mydict)) # sorry it cannot return a sorted dict :)
[-1, 1, 4] # maybe an OrderedDict in the future...
Scorer
The Scorer
is a dict
subclass for scoring hashable items. It generalizes functionality of built-in Counter
to floating-point numbers with full math operation support.
>>> from izy import Scorer
>>> s1 = Scorer({'a': 1, 'b': 2, 'c': 5})
>>> s1['d'] = 3
>>> s1
Scorer({c: 5, d: 3, b: 2, a: 1})
>>> s2 = Scorer('abc', [-2, 3, 4])
>>> s2
Scorer({c: 4, b: 3, a: -2})
Mathematical operators (+
, -
, *
, /
, //
, %
, **
) are supported for both Scorer
and scalar right-hand operands.
>>> s1 + s2
Scorer({c: 9, b: 5, d: 3, a: -1})
>>> s1 / 4
Scorer({c: 1.25, d: 0.75, b: 0.5, a: 0.25})
WARNING! To support partial update with math operations, we carry non-common items from the first operand unchanged, but those from the second operand are ignored.
Unary math operators (+
, -
) are available too.
>>> +s2 # special usage for useless uniary `+` (only keeps positive itmes)
Scorer({c: 4, b: 3})
>>> s1 + (+s2) # not equivalent to s1 + s2
Scorer({c: 9, b: 5, d: 3, a: 1})
We also have abs()
, round()
:
>>> abs(s2)
Scorer({c: 4, b: 3, a: 2})
Logical operators &
, |
apply element-wise min/max and they are also applicable to scalars. As Scorer
is not a set
or even multiset
(like Counter
), we don't refer to these as intersection and union, but the functionalities are still similar.
>>> s1 & s2 # ~ min (drops non-common items)
Scorer({c: 4, b: 2, a: -2})
>>> s1 & 2 # drops items with score less than 2
Scorer({c: 5, d: 3, b: 2})
>>> s1 | s2 # ~ max
Scorer({c: 5, b: 3, d: 3, a: 1})
About the above warning, note that
(s1 | (s1 & s2))
gives the subset ofs1
which also exists ins2
. You can use this to force math operations to return common items only.
And finally the ultimate goal of the Scorer
is to sort its items according to scores and give us the best
, topk
(or worst
, bottomk
).
>>> s1.best()
('c', 5)
>>> s1.topk(3) # alias to `s1.best` but more readable when you specify the number of items
[('c', 5), ('d', 3), ('b', 2)]
>>> s1.topk(-2) # negative k means bottom k
[('a', 1), ('b', 2)]
>>> s1.ascending() # prefer this to `best` or `topk` with special values of n or k (None, 0, inf)
[('a', 1), ('b', 2), ('d', 3), ('c', 5)]
>>> s1.median() # if scorer length is even, lower median is returned
('b', 2)
Decorators
Python functools
is really interesting, but it really lacks some generally usefull decorators.
First, @returns()
and @yields()
make your function/generator return/yield namedtuple
s to more pythonically access your function output. It also looks like an easy documentation to me (about the meaning of what function returns and not just the type
).
@returns('x', 'plus_one')
def myfunction(x):
return x, x+1
@yields('a', 'a_doubled')
def mygenerator(x):
for i in range(x):
yield {'a':i, 'a_doubled': i*2}
n = myfunction(5).plus_one
@returns_time()
calculates function runtime and returns it as a datetime.timedelta
object. You can change time format to milis
(int
) or seconds
(float
). It returns a namedtuple
which you can rename using @returns
.
@returns_time()
def timed(x):
z = 0
for i in range(x * 1000000):
z += i
@returns('output', 'milis')
@returns_time(milis=True)
def timed_milis(x):
z = 0
for i in range(x * 1000000):
z += i
return 'done'
>>> timed(64)
timed_output(output=None, time=datetime.timedelta(seconds=2, microseconds=530048))
>>> timed_milis(32)
timed_milis_output(output='done', milis=1289)
@logs()
does what it says at three stages: before calling, after returning and on exceptions. You can control log level for each stage, log to_file
using default logger (named after the function) or pass your own logging.Logger
.
@logs(before=logging.DEBUG, after=logging.INFO, to_file='logged.log')
def logged(x, **kw):
for i in range(1000000):
x += i
>>> logged(1, key1=5, key2=7.2)
[2021-12-31 08:56:33][logged][DEBUG] - Function `logged` called with args: (4, key1=5, key2=7.2)
[2021-12-31 08:56:33][logged][INFO] - Function `logged` returned after 0:00:00.029084 with result: None
@fix_this()
reminds you to fix something in stronger way than a passive comment. It raises UserWarning
at runtime and does this everytime :)
@fix_this('It always prints ValueError, errors should be raised!')
def please(x):
print('ValueError')
This one @ignores()
given exceptions (and returns None
). Who knows when and why you need this? :) You can stack it on top of @logs()
to be aware of ignored exceptions.
@ignores(ValueError, IndexError)
@logs()
def ignorer(x):
for i in range(x):
raise ValueError
Want more useful exception handler? @fallsback()
falls back on specified exception to predefined return value or another callable
. For multiple exceptions, stack it like this:
@fallsback(ZeroDivisionError, 1)
@fallsback(ValueError, lambda x: x**2)
def multifall2callable(x):
if x < 0:
raise ValueError
else:
raise ZeroDivisionError