Great fancy list construction in Python

Out of curiosity, I discovered the potential of ellipse Object in Python (...) and I discovered that it does not do much except a handful of minor features. To make it useful, I decided to create the designer with the most chic pants for a list that I could.

The function, super_list, takes any number of arguments to add to the list. Here are the functions:

  • super_list (multiple arguments, specified) -> Generates a list with the specified arguments. If an argument does not follow any of the specifics listed below, it is simply appended to the array at the proper nesting level. This example returns [multiple, arguments, provided]a list of arguments.

  • super_list (5, ..., 9) -> Use the ellipse Object to create something that looks like "x to y" or an area. This particular example would contain a list with [5,6,7,8,9]the number between 5 and 9.

  • super_list (arg, array.move_up, higher_arg, array.move_down, lower_arg) -> Sets the nesting level in the list. Including array.move_up or array.move_down moves a level of nesting up or down in the list. This example generates [arg, [higher_arg]lower_arg]Move the array chain up and down array.move_up and array.move_down,

One last great example:

super_list ("first level", 5, ..., 9, array.move_up, array.move_up, "second level", 10, ..., 15, array.move_down, "one level down")


['first level', 5, 6, 7, 8, 9, [['second level', 10, 11, 12, 13, 14, 15]"One level down"]]

So that's my current implementation:

def get_in_list (lst, indexes):
"" "Retrieves an item in a nested list from an index list." ""
return functools.reduce (operator.getitem, indexes, lst)

def super_list (* args):
"" "Special initialization syntax for lists." ""
curr_index = []
  Result = []
  for index: enumerated element (arguments): # iterate arguments with indexes
el_type = type (...) # Type of Ellipsis object
ifinstance (item, el_type): # case: Ellipse range generator
if index == 0:
get_in_list (result, curr_index) .append (item)
get_in_list (result, curr_index) .extend (list (range (args[index-1]+1, args[index+1])))
elif item == array.move_up: # Uppercase / Lowercase: Move one level up in the list
get_in_list (result, curr_index) .append ([])
curr_index.append (len (get_in_list (result, curr_index)) - 1)
elif item == array.move_down: # case: Move one level down the list
To attempt:
curr_index.pop ()
except IndexError: # Unintentionally start when the user attempts to move too far down the list
else: # case: No special syntax - add item to list regularly
get_in_list (result, curr_index) .append (item)
Return result

get_in_list is a function that retrieves an item from a list of indexes. It means that on[0][1] == get_in_list (a, [0, 1]),

My questions:

  • Is it too messy?

  • Is something too long and could be implemented shorter?

  • Is the program too confusing and could it be more detailed?

Of course, all the other comments you want to add are very welcome. Thank you in advance!

Compiler – Understand the rules of table construction

I'm studying top-down parsing, especially LL (1) parsing. However, I can not understand what rules mean.

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Example Grammer is like that

S → (S) S | $ epsilon $

How can I derive as follows?

Enter the image description here

I have read all explanations of the textbook, but I can not fully understand the process of table building. Is there someone who can explain this process more easily?

at.algebraic topology – If the Tate construction disappears for all insignificant $ G $ actions, then it disappears for all $ G $ actions.

To let $ mathcal {C} $ be half-additive $ infty $category, complete and cocomplete, and let $ G $ to be a finite group. Then for everyone $ X in Fun (BG, mathcal {C}) $there is a standard card $ N_X: X_G to X ^ G $, For each $ X in mathcal {C} $We have the constant $ X ^ {triv} in Fun (BG, mathcal {C}) $, Suppose that $ N_ {X ^ {triv}} $ is an equivalence for everyone $ X in mathcal $, Then it follows that $ N_X $ is an equivalence for everyone $ X in Fun (BG, mathcal {C}) $?

Evidence that this might be true comes from thinking about ambidexterity: The question is whether n-ambidexterity can be tested on trivial objects $ n = 1 $, Note that this is the case when $ n = (- 2), (- 1) $ (vacuum) or $ n = 0 $ (If a spiky category $ mathcal $ has finite coproducts and finite products, and if $ X vee X to X times X $ is an equivalence for everyone $ X in mathcal $, then $ X vee Y to X times Y $ is an equivalence for everyone $ X, Y in mathcal $).

Really, I'm interested in the question for everyone $ n in mathbb N $:

Question: To let $ mathcal $ Bean $ (n-1) $-beidhändig $ infty $Category, complete and complementary. To let $ B $ Bean $ n $Space with finite homotopy groups. Then for all $ X in Fun (B, mathcal C) $there is a standard card $ N_X: varinjlim X to varprojlim X $, Suppose this card is an equivalence, though $ X $ is constant. Then $ N_X $ an equivalence for all $ X $?

Maybe this is not "local" (ie for a landline) $ B $). Then we can at least say that, if $ N_X $ is an equivalence for all constants $ X $ and everything $ n $-controlled, $ pi $-Finally $ B $, then $ mathcal $ is $ n $-beidhändig?

Interior decoration and construction

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c ++ – spdlog logger construction – make_unique does not compile

I would like to have a spdlog logger in my class as a private member, which is even suggested in the documentation. First disappointment: No copying or moving the constructor for spdlog :: logger. So if I want a more complex logger, I have to jump through some tires. Let's ignore that and just use a unique_ptr.

I can not make a unique pointer from a logger with make_unique. Doing "manual" works well.

std :: unique_ptr logger;

// is working!

spdlog :: logger * tmp = new spdlog :: logger ("logger", {console_sink, file_sink});
logger.reset (tmp);

// DO NOT compile! "No matching function call to make_unique" - why?
logger = std :: make_unique ("logger", {console_sink, file_sink});

Why does not the call to make_unique work?

at.algebraic topology – Two models for the classification space of a subgroup on geoemetric pole construction

To let $ H $ be a topological group that is a subset of two other topological groups $ G $ and $ G & # 39; $, It follows (from Rmk 8.9 in the following work) that weak equilibria exist $ B (*, G, G / H) to BH $ and $ B (*, G & # 39 ;, G & # 39; / H) to BH $,

One of the reasons why you want to look at such a model $ BH $ would be if you understand $ G $ and $ G / H $ (and $ G & # 39; $ and $ G & # 39; / H $) better than $ H $, Of course, now I could see the weak equivalence between $ B (*, G, G / H) $ and $ B (*, G #, G # / H) $ through the following zigzags of weak equivalences
$$ B (*, G, G / H) xrightarrow sim BH xleftarrow sim B (*, G & # 39 ;, G & # 39; / H).

But I do not "understand" $ H $ I want to recognize the weak equivalence between $ B (*, G, G / H) $ and $ B (*, G #, G # / H) $ without use $ H $but use constructions that are used $ G $, $ G & # 39; $, $ G / H $, $ G & # 39; / H $ etc … Is that even possible?

Lumix GX9 construction and weather protection quality as a travel camera

I am aware that Panasonic Lumix GX9 is not weatherproof.

I would like to use it as a travel camera, that is, all sorts of weather factors, sometimes thrown without cover in backpacking through the mountains …

Will GX9 build quality be good enough to cope with such behavior or is it better to take care of GX8?

I love USB charging and flip screen, which is more discreet compared to GX8

Many Thanks

complex geometry – The construction of a basis of holomorphic differential 1-forms for a given plane curve

Consider the complex numbers and consider a function $ F left (x, y right) $ and a curve $ C $ defined by $ F left (x, y right) = 0 $,

I know that to construct the sort associated with Jacob $ C $one integrates a basis of global holomorphic differential forms over the contours of the homology group of the curve. I am looking for information that is based on concrete calculations for specific examples. Everything I've seen so far has been meaningless abstract or unspecific. Note: I'm new to this area – I'm an analyst who knows next to nothing about algebra, even less about differential geometry or topology.

In search of a reasonable answer, I turned to the wonderful (albeit densely written) text of H. F. Baker of the early 20th century. Reading the first few pages makes it easy plentiful It will be appreciated that there is a general method of creating a basis of holomorphic differential forms for a given curve. Ted Shifrin's comment on this math stack exchange problem only makes me more confident than ever that the answers I seek are out there somewhere.

By and large, my goals are as follows. My goal is to be able to use the answers to these questions to compute various concrete examples, either manually or with the help of a computer algebra system. Therefore I am looking for formulas, explanations and / or stepwise procedures / algorithms and / or relevant reference / reading material.

(1) In the case where $ F $ is a polynomial, what is / are the procedure (s) for determining a basis of holomorphic differential 1 forms $ F $? When the method varies depending on certain characteristics of $ F $ (say, if $ F $ is an affine curve or a projective curve or of a certain shape or a similar detail), what are these variations?

(2) In the case where $ F $ is a polynomial of $ x $-Degree $ d_ {x} $, $ y $-Degree $ d_ {y} $, and $ C $ is a curve of the genus $ g $I know that the basis of holomorphic differential 1-forms for $ C $ will be of dimension $ g $, In that case we say where $ C $ is an elliptic curve with:

$$ F left (x, y right) = 4x ^ {3} -g_ {2} x-g_ {3} -y ^ {2} $$

the classic Jacobi inversion problem arises from the consideration of a function $ wp left (z right) $ which parameterizes $ C $in that sense that $ F left ( wp left (z right), wp ^ { prime} left (z right) right) $ is zero. With the equation: $$ F left ( wp left (z right), wp ^ { prime} left (z right) right) = 0 $$ we can write: $$ wp ^ {- 1} left (z right) = int_ {z_ {0}} ^ {z} frac {ds} {4s ^ {3} -g_ {2} s-g_ {3 }} $$ and know that the multiplicity of the integral then reflects the structure of the Jacobian variety $ C $,

That being said, in the case where $ C $ is of the genus $ g geq2 $and where we can write $ F left (x, y right) = 0 $
as: $$ y = textrm {algebraic function of} x $$ Nothing prevents us from performing exactly the same calculation as in the case of an elliptic curve. Of course, this calculation must be wrong. my question is: where and how is it going wrong?? How would the parameterization function obtained in this way relate to the "true" parameterization function – the associated multivariable Abel function $ C $? In addition, how can this calculation, if any, be changed in order to generate the correct parameterization function (Abel function)?

(3) I hope that by understanding (1) and (2) I am able to see what happens when these classical techniques are applied not algebraic even curves defined with $ F $ now an analytic function (with exponential functions and other transcendental functions in addition to polynomials). Of particular interest to me are the transcendental curves associated with exponential Diophantine equations, such as: $$ a ^ {x} -b ^ {y} = c $$
$$ y ^ {n} = b ^ {x} -a $$

I wonder if this has already happened. If so, links and references would be very welcome.

Even so, I would like to know the answers to my previous questions, even if it's just for my personal edification.

Thank you in advance!