@ -681,7 +681,7 @@ to_exclusive = <range>.stop
< ul >
< li > < strong > Use < code class = "python hljs" > < span class = "hljs-string" > '< D/DT> .weekday()'< / span > < / code > to get the day of the week (Mon == 0).< / strong > < / li >
< li > < strong > < code class = "python hljs" > < span class = "hljs-string" > 'fold=1'< / span > < / code > means the second pass in case of time jumping back for one hour.< / strong > < / li >
< li > < strong > < code class = "python hljs" > < span class = "hljs-string" > '< DTa> = resolve_imaginary(< DTa> )'< / span > < / code > fixes DTs that fall into missing hour.< / strong > < / li >
< li > < strong > < code class = "python hljs" > < span class = "hljs-string" > '< DTa> = resolve_imaginary(< DTa> )'< / span > < / code > fixes DTs that fall into the missing hour.< / strong > < / li >
< / ul >
< div > < h3 id = "now" > Now< / h3 > < pre > < code class = "python language-python hljs" > < D/DTn> = D/DT.today() < span class = "hljs-comment" > # Current local date or naive datetime.< / span >
< DTn> = DT.utcnow() < span class = "hljs-comment" > # Naive datetime from current UTC time.< / span >
@ -781,45 +781,41 @@ func(*args, **kwargs)
< span class = "hljs-function" > < span class = "hljs-keyword" > def< / span > < span class = "hljs-title" > f< / span > < span class = "hljs-params" > (*args, y, **kwargs)< / span > :< / span > < span class = "hljs-comment" > # f(x=1, y=2, z=3) | f(1, y=2, z=3)< / span >
< span class = "hljs-function" > < span class = "hljs-keyword" > def< / span > < span class = "hljs-title" > f< / span > < span class = "hljs-params" > (x, *args, z, **kwargs)< / span > :< / span > < span class = "hljs-comment" > # f(x=1, y=2, z=3) | f(1, y=2, z=3) | f(1, 2, z=3)< / span >
< / code > < / pre >
< div > < h3 id = "otheruses" > Other Uses< / h3 > < pre > < code class = "python language-python hljs" > < list> = [*< collection> [, ...]]
< set> = {*< collection> [, ...]}
< tuple > = (*< collection> , [...])
< dict> = {**< dict> [, ...]}
< div > < h3 id = "otheruses" > Other Uses< / h3 > < pre > < code class = "python language-python hljs" > < list> = [*< collection> [, ...]]
< set> = {*< collection> [, ...]}
< tup. > = (*< collection> , [...])
< dict> = {**< dict> [, ...]}
< / code > < / pre > < / div >
< pre > < code class = "python language-python hljs" > head, *body, tail = < collection>
< / code > < / pre >
< div > < h2 id = "inline" > < a href = "#inline" name = "inline" > #< / a > Inline< / h2 > < div > < h3 id = "lambda" > Lambda< / h3 > < pre > < code class = "python language-python hljs" > < function > = < span class = "hljs-keyword" > lambda< / span > : < return_value>
< function > = < span class = "hljs-keyword" > lambda< / span > < argument _1> , < argument _2> : < return_value>
< div > < h2 id = "inline" > < a href = "#inline" name = "inline" > #< / a > Inline< / h2 > < div > < h3 id = "lambda" > Lambda< / h3 > < pre > < code class = "python language-python hljs" > < func> = < span class = "hljs-keyword" > lambda< / span > : < return_value>
< func> = < span class = "hljs-keyword" > lambda< / span > < arg_1> , < arg_2> : < return_value>
< / code > < / pre > < / div > < / div >
< div > < h3 id = "comprehensions" > Comprehensions< / h3 > < pre > < code class = "python language-python hljs" > < list> = [i+< span class = "hljs-number" > 1< / span > < span class = "hljs-keyword" > for< / span > i < span class = "hljs-keyword" > in< / span > range(< span class = "hljs-number" > 10< / span > )] < span class = "hljs-comment" > # [1, 2, ..., 10]< / span >
< set> = {i < span class = "hljs-keyword" > for< / span > i < span class = "hljs-keyword" > in< / span > range(< span class = "hljs-number" > 10< / span > ) < span class = "hljs-keyword" > if< / span > i > < span class = "hljs-number" > 5< / span > } < span class = "hljs-comment" > # {6, 7, 8, 9}< / span >
< iter> = (i+< span class = "hljs-number" > 5< / span > < span class = "hljs-keyword" > for< / span > i < span class = "hljs-keyword" > in< / span > range(< span class = "hljs-number" > 10< / span > )) < span class = "hljs-comment" > # (5, 6, ..., 14)< / span >
< dict> = {i: i*< span class = "hljs-number" > 2< / span > < span class = "hljs-keyword" > for< / span > i < span class = "hljs-keyword" > in< / span > range(< span class = "hljs-number" > 10< / span > )} < span class = "hljs-comment" > # {0: 0, 1: 2, ..., 9: 18}< / span >
< div > < h3 id = "comprehensions" > Comprehensions< / h3 > < pre > < code class = "python language-python hljs" > < list> = [i+< span class = "hljs-number" > 1< / span > < span class = "hljs-keyword" > for< / span > i < span class = "hljs-keyword" > in< / span > range(< span class = "hljs-number" > 10< / span > )] < span class = "hljs-comment" > # [1, 2, ..., 10]< / span >
< set> = {i < span class = "hljs-keyword" > for< / span > i < span class = "hljs-keyword" > in< / span > range(< span class = "hljs-number" > 10< / span > ) < span class = "hljs-keyword" > if< / span > i > < span class = "hljs-number" > 5< / span > } < span class = "hljs-comment" > # {6, 7, 8, 9}< / span >
< iter> = (i+< span class = "hljs-number" > 5< / span > < span class = "hljs-keyword" > for< / span > i < span class = "hljs-keyword" > in< / span > range(< span class = "hljs-number" > 10< / span > )) < span class = "hljs-comment" > # (5, 6, ..., 14)< / span >
< dict> = {i: i*< span class = "hljs-number" > 2< / span > < span class = "hljs-keyword" > for< / span > i < span class = "hljs-keyword" > in< / span > range(< span class = "hljs-number" > 10< / span > )} < span class = "hljs-comment" > # {0: 0, 1: 2, ..., 9: 18}< / span >
< / code > < / pre > < / div >
< pre > < code class = "python language-python hljs" > out = [i+j < span class = "hljs-keyword" > for< / span > i < span class = "hljs-keyword" > in< / span > range(< span class = "hljs-number" > 10< / span > ) < span class = "hljs-keyword" > for< / span > j < span class = "hljs-keyword" > in< / span > range(< span class = "hljs-number" > 10< / span > )]
< pre > < code class = "python language-python hljs" > < span class = "hljs-meta" > > > > < / span > [l+r < span class = "hljs-keyword" > for< / span > l < span class = "hljs-keyword" > in< / span > < span class = "hljs-string" > 'abc'< / span > < span class = "hljs-keyword" > for< / span > r < span class = "hljs-keyword" > in< / span > < span class = "hljs-string" > 'abc'< / span > ]
[< span class = "hljs-string" > 'aa'< / span > , < span class = "hljs-string" > 'ab'< / span > , < span class = "hljs-string" > 'ac'< / span > , ..., < span class = "hljs-string" > 'cc'< / span > ]
< / code > < / pre >
< div > < h4 id = "isthesameas-1" > Is the same as:< / h4 > < pre > < code class = "python language-python hljs" > out = []
< span class = "hljs-keyword" > for< / span > i < span class = "hljs-keyword" > in< / span > range(< span class = "hljs-number" > 10< / span > ):
< span class = "hljs-keyword" > for< / span > j < span class = "hljs-keyword" > in< / span > range(< span class = "hljs-number" > 10< / span > ):
out.append(i+j)
< div > < h3 id = "mapfilterreduce" > Map, Filter, Reduce< / h3 > < pre > < code class = "python language-python hljs" > < iter> = map(< span class = "hljs-keyword" > lambda< / span > x: x + < span class = "hljs-number" > 1< / span > , range(< span class = "hljs-number" > 10< / span > )) < span class = "hljs-comment" > # (1, 2, ..., 10)< / span >
< iter> = filter(< span class = "hljs-keyword" > lambda< / span > x: x > < span class = "hljs-number" > 5< / span > , range(< span class = "hljs-number" > 10< / span > )) < span class = "hljs-comment" > # (6, 7, 8, 9)< / span >
< obj> = reduce(< span class = "hljs-keyword" > lambda< / span > out, x: out + x, range(< span class = "hljs-number" > 10< / span > )) < span class = "hljs-comment" > # 45< / span >
< / code > < / pre > < / div >
< div > < h3 id = "mapfilterreduce" > Map, Filter, Reduce< / h3 > < pre > < code class = "python language-python hljs" > < span class = "hljs-keyword" > from< / span > functools < span class = "hljs-keyword" > import< / span > reduce
< iter> = map(< span class = "hljs-keyword" > lambda< / span > x: x + < span class = "hljs-number" > 1< / span > , range(< span class = "hljs-number" > 10< / span > )) < span class = "hljs-comment" > # (1, 2, ..., 10)< / span >
< iter> = filter(< span class = "hljs-keyword" > lambda< / span > x: x > < span class = "hljs-number" > 5< / span > , range(< span class = "hljs-number" > 10< / span > )) < span class = "hljs-comment" > # (6, 7, 8, 9)< / span >
< obj> = reduce(< span class = "hljs-keyword" > lambda< / span > out, x: out + x, range(< span class = "hljs-number" > 10< / span > )) < span class = "hljs-comment" > # 45< / span >
< / code > < / pre > < / div >
< div > < h3 id = "anyall" > Any, All< / h3 > < pre > < code class = "python language-python hljs" > < bool> = any(< collection> ) < span class = "hljs-comment" > # False if empty.< / span >
< bool> = all(el[< span class = "hljs-number" > 1< / span > ] < span class = "hljs-keyword" > for< / span > el < span class = "hljs-keyword" > in< / span > < collection> ) < span class = "hljs-comment" > # True if empty.< / span >
< ul >
< li > < strong > Reduce must be imported from functools module.< / strong > < / li >
< / ul >
< div > < h3 id = "anyall" > Any, All< / h3 > < pre > < code class = "python language-python hljs" > < bool> = any(< collection> ) < span class = "hljs-comment" > # False if empty.< / span >
< bool> = all(el[< span class = "hljs-number" > 1< / span > ] < span class = "hljs-keyword" > for< / span > el < span class = "hljs-keyword" > in< / span > < collection> ) < span class = "hljs-comment" > # True if empty.< / span >
< / code > < / pre > < / div >
< div > < h3 id = "ifelse" > If - Else < / h3 > < pre > < code class = "python language-python hljs" > < obj> = < expression _if_true> < span class = "hljs-keyword" > if< / span > < condition> < span class = "hljs-keyword" > else< / span > < expression _if_false>
< div > < h3 id = "conditionalexpression" > Conditional Expression< / h3 > < pre > < code class = "python language-python hljs" > < obj> = < exp_if_true> < span class = "hljs-keyword" > if< / span > < condition> < span class = "hljs-keyword" > else< / span > < exp_if_false>
< / code > < / pre > < / div >
< pre > < code class = "python language-python hljs" > < span class = "hljs-meta" > > > > < / span > [a < span class = "hljs-keyword" > if< / span > a < span class = "hljs-keyword" > else< / span > < span class = "hljs-string" > 'zero'< / span > < span class = "hljs-keyword" > for< / span > a < span class = "hljs-keyword" > in< / span > (< span class = "hljs-number" > 0< / span > , < span class = "hljs-number" > 1< / span > , < span class = "hljs-number" > 2< / span > , < span class = "hljs-number" > 3< / span > )]
@ -835,7 +831,7 @@ Direction = Enum(<span class="hljs-string">'Direction'</span>, <span class="hljs
direction = Direction.n
< / code > < / pre >
< pre > < code class = "python language-python hljs" > < span class = "hljs-keyword" > from< / span > dataclasses < span class = "hljs-keyword" > import< / span > make_dataclass
Creature = make_dataclass(< span class = "hljs-string" > 'Creature'< / span > , [< span class = "hljs-string" > 'location '< / span > , < span class = "hljs-string" > 'direction '< / span > ])
Creature = make_dataclass(< span class = "hljs-string" > 'Creature'< / span > , [< span class = "hljs-string" > 'loc'< / span > , < span class = "hljs-string" > 'dir'< / span > ])
creature = Creature(Point(< span class = "hljs-number" > 0< / span > , < span class = "hljs-number" > 0< / span > ), Direction.n)
< / code > < / pre >
< div > < h2 id = "closure" > < a href = "#closure" name = "closure" > #< / a > Closure< / h2 > < p > < strong > We have a closure in Python when:< / strong > < / p > < ul >
@ -884,7 +880,7 @@ creature = Creature(Point(<span class="hljs-number">0</span>, <span class="hljs
< span class = "hljs-meta" > > > > < / span > counter(), counter(), counter()
(< span class = "hljs-number" > 1< / span > , < span class = "hljs-number" > 2< / span > , < span class = "hljs-number" > 3< / span > )
< / code > < / pre >
< div > < h2 id = "decorator" > < a href = "#decorator" name = "decorator" > #< / a > Decorator< / h2 > < p > < strong > A decorator takes a function, adds some functionality and returns it.< / strong > < / p > < pre > < code class = "python language-python hljs" > < span class = "hljs-meta" > @decorator_name< / span >
< div class = "pagebreak" > < / div > < div > < h2 id = "decorator" > < a href = "#decorator" name = "decorator" > #< / a > Decorator< / h2 > < p > < strong > A decorator takes a function, adds some functionality and returns it.< / strong > < / p > < pre > < code class = "python language-python hljs" > < span class = "hljs-meta" > @decorator_name< / span >
< span class = "hljs-function" > < span class = "hljs-keyword" > def< / span > < span class = "hljs-title" > function_that_gets_passed_to_decorator< / span > < span class = "hljs-params" > ()< / span > :< / span >
...
< / code > < / pre > < / div >
@ -1397,7 +1393,7 @@ sys.exit(<int>) <span class="hljs-comment"># Exits with
< / code > < / pre > < / div >
< div class = "pagebreak" > < / div > < div > < h2 id = "print" > < a href = "#print" name = "print" > #< / a > Print< / h2 > < pre > < code class = "python language-python hljs" > print(< el_1> , ..., sep=< span class = "hljs-string" > ' '< / span > , end=< span class = "hljs-string" > '\n'< / span > , file=sys.stdout, flush=< span class = "hljs-keyword" > False< / span > )
< div > < h2 id = "print" > < a href = "#print" name = "print" > #< / a > Print< / h2 > < pre > < code class = "python language-python hljs" > print(< el_1> , ..., sep=< span class = "hljs-string" > ' '< / span > , end=< span class = "hljs-string" > '\n'< / span > , file=sys.stdout, flush=< span class = "hljs-keyword" > False< / span > )
< / code > < / pre > < / div >
< ul >
@ -1756,19 +1752,18 @@ CompletedProcess(args=[<span class="hljs-string">'bc'</span>, <span class="hljs-
< li > < strong > Module that performs conversions between a sequence of numbers and a bytes object.< / strong > < / li >
< li > < strong > Machine’s native type sizes and byte order are used by default.< / strong > < / li >
< / ul > < pre > < code class = "python language-python hljs" > < span class = "hljs-keyword" > from< / span > struct < span class = "hljs-keyword" > import< / span > pack, unpack, iter_unpack
< bytes> = pack(< span class = "hljs-string" > '< format> '< / span > , < num_1> [, < num_2> , ...])
< tuple> = unpack(< span class = "hljs-string" > '< format> '< / span > , < bytes> )
< tuples> = iter_unpack(< span class = "hljs-string" > '< format> '< / span > , < bytes> )
< / code > < / pre > < / div >
< div > < h3 id = "example-1" > Example< / h3 > < pre > < code class = "python language-python hljs" > < span class = "hljs-meta" > > > > < / span > pack(< span class = "hljs-string" > '> hhl'< / span > , < span class = "hljs-number" > 1< / span > , < span class = "hljs-number" > 2< / span > , < span class = "hljs-number" > 3< / span > )
< pre > < code class = "python language-python hljs" > < bytes> = pack(< span class = "hljs-string" > '< format> '< / span > , < num_1> [, < num_2> , ...])
< tuple> = unpack(< span class = "hljs-string" > '< format> '< / span > , < bytes> )
< tuples> = iter_unpack(< span class = "hljs-string" > '< format> '< / span > , < bytes> )
< / code > < / pre >
< pre > < code class = "python language-python hljs" > < span class = "hljs-meta" > > > > < / span > pack(< span class = "hljs-string" > '> hhl'< / span > , < span class = "hljs-number" > 1< / span > , < span class = "hljs-number" > 2< / span > , < span class = "hljs-number" > 3< / span > )
< span class = "hljs-string" > b'\x00\x01\x00\x02\x00\x00\x00\x03'< / span >
< span class = "hljs-meta" > > > > < / span > unpack(< span class = "hljs-string" > '> hhl'< / span > , < span class = "hljs-string" > b'\x00\x01\x00\x02\x00\x00\x00\x03'< / span > )
(< span class = "hljs-number" > 1< / span > , < span class = "hljs-number" > 2< / span > , < span class = "hljs-number" > 3< / span > )
< / code > < / pre > < / div >
< / code > < / pre >
< div > < h3 id = "format-2" > Format< / h3 > < div > < h4 id = "forstandardtypesizesstartformatstringwith" > For standard type sizes start format string with:< / h4 > < ul >
< li > < strong > < code class = "python hljs" > < span class = "hljs-string" > '='< / span > < / code > - native byte order (usually little-endian)< / strong > < / li >
< li > < strong > < code class = "python hljs" > < span class = "hljs-string" > '< '< / span > < / code > - little-endian< / strong > < / li >
@ -1835,6 +1830,7 @@ CompletedProcess(args=[<span class="hljs-string">'bc'</span>, <span class="hljs-
< li > < strong > CPython interpreter can only run a single thread at a time.< / strong > < / li >
< li > < strong > That is why using multiple threads won't result in a faster execution, unless at least one of the threads contains an I/O operation.< / strong > < / li >
< / ul > < pre > < code class = "python language-python hljs" > < span class = "hljs-keyword" > from< / span > threading < span class = "hljs-keyword" > import< / span > Thread, RLock, Semaphore, Event, Barrier
< span class = "hljs-keyword" > from< / span > concurrent.futures < span class = "hljs-keyword" > import< / span > ThreadPoolExecutor
< / code > < / pre > < / div >
@ -1863,13 +1859,11 @@ CompletedProcess(args=[<span class="hljs-string">'bc'</span>, <span class="hljs-
< Barrier> = Barrier(n_times) < span class = "hljs-comment" > # Wait() blocks until it's called n_times.< / span >
< / code > < / pre > < / div >
< div > < h3 id = "threadpoolexecutor" > Thread Pool Executor< / h3 > < p > < strong > Object that manages thread execution.< / strong > < / p > < pre > < code class = "python language-python hljs" > < span class = "hljs-keyword" > from< / span > concurrent.futures < span class = "hljs-keyword" > import< / span > ThreadPoolExecutor
< div > < h3 id = "threadpoolexecutor" > Thread Pool Executor< / h3 > < p > < strong > Object that manages thread execution.< / strong > < / p > < pre > < code class = "python language-python hljs" > < Exec> = ThreadPoolExecutor(max_workers=< span class = "hljs-keyword" > None< / span > ) < span class = "hljs-comment" > # Or: `with ThreadPoolExecutor() as < name> : …`< / span >
< Exec> .shutdown(wait=< span class = "hljs-keyword" > True< / span > ) < span class = "hljs-comment" > # Blocks until all threads finish executing.< / span >
< / code > < / pre > < / div >
< pre > < code class = "python language-python hljs" > < Exec> = ThreadPoolExecutor(max_workers=< span class = "hljs-keyword" > None< / span > ) < span class = "hljs-comment" > # Or: `with ThreadPoolExecutor() as < name> : …`< / span >
< Exec> .shutdown(wait=< span class = "hljs-keyword" > True< / span > ) < span class = "hljs-comment" > # Blocks until all threads finish executing.< / span >
< / code > < / pre >
< pre > < code class = "python language-python hljs" > < iter> = < Exec> .map(< func> , < args_1> , ...) < span class = "hljs-comment" > # A multithreaded and non-lazy map().< / span >
< Futr> = < Exec> .submit(< func> , < arg_1> , ...) < span class = "hljs-comment" > # Starts a thread and returns its Future object.< / span >
< bool> = < Futr> .done() < span class = "hljs-comment" > # Checks if the thread has finished executing.< / span >
@ -2303,7 +2297,7 @@ right = [[<span class="hljs-number">0.1</span> , <span class="hljs-number">0.6<
right = [[< span class = "hljs-number" > 0.1< / span > , < span class = "hljs-number" > 0.6< / span > , < span class = "hljs-number" > 0.8< / span > ], [< span class = "hljs-number" > 0.1< / span > , < span class = "hljs-number" > 0.6< / span > , < span class = "hljs-number" > 0.8< / span > ], [< span class = "hljs-number" > 0.1< / span > , < span class = "hljs-number" > 0.6< / span > , < span class = "hljs-number" > 0.8< / span > ]] < span class = "hljs-comment" > # Shape: (3, 3) < - !< / span >
< / code > < / pre > < / div >
< div > < h4 id = "3ifneithernonmatchingdimensionhassize1raiseanerror" > 3. If neither non-matching dimension has size 1, raise an error.< / h4 > < div > < h3 id = "example-2 " > Example< / h3 > < div > < h4 id = "foreachpointreturnsindexofitsnearestpoint010608121" > For each point returns index of its nearest point (< code class = "python hljs" > [< span class = "hljs-number" > 0.1< / span > , < span class = "hljs-number" > 0.6< / span > , < span class = "hljs-number" > 0.8< / span > ] => [< span class = "hljs-number" > 1< / span > , < span class = "hljs-number" > 2< / span > , < span class = "hljs-number" > 1< / span > ]< / code > ):< / h4 > < pre > < code class = "python language-python hljs" > < span class = "hljs-meta" > > > > < / span > points = np.array([< span class = "hljs-number" > 0.1< / span > , < span class = "hljs-number" > 0.6< / span > , < span class = "hljs-number" > 0.8< / span > ])
< div > < h4 id = "3ifneithernonmatchingdimensionhassize1raiseanerror" > 3. If neither non-matching dimension has size 1, raise an error.< / h4 > < div > < h3 id = "example-1 " > Example< / h3 > < div > < h4 id = "foreachpointreturnsindexofitsnearestpoint010608121" > For each point returns index of its nearest point (< code class = "python hljs" > [< span class = "hljs-number" > 0.1< / span > , < span class = "hljs-number" > 0.6< / span > , < span class = "hljs-number" > 0.8< / span > ] => [< span class = "hljs-number" > 1< / span > , < span class = "hljs-number" > 2< / span > , < span class = "hljs-number" > 1< / span > ]< / code > ):< / h4 > < pre > < code class = "python language-python hljs" > < span class = "hljs-meta" > > > > < / span > points = np.array([< span class = "hljs-number" > 0.1< / span > , < span class = "hljs-number" > 0.6< / span > , < span class = "hljs-number" > 0.8< / span > ])
[ < span class = "hljs-number" > 0.1< / span > , < span class = "hljs-number" > 0.6< / span > , < span class = "hljs-number" > 0.8< / span > ]
< span class = "hljs-meta" > > > > < / span > wrapped_points = points.reshape(< span class = "hljs-number" > 3< / span > , < span class = "hljs-number" > 1< / span > )
[[ < span class = "hljs-number" > 0.1< / span > ],
Jure Šorn
3 years ago