generator

问题 I'd like to train a convolutional network to solve a multi-class, multi-label problem on image data. Due to the nature of the data, and for reasons I'll spare you, it would be best if I could use a custom R generator function to feed to the fit_generator command, instead of its built-in image_data_generator and flow_images_from_directory commands (which I was successfully able to get working, just not for this particular problem). Here (https://www.rdocumentation.org/packages/keras/versions/2

问题 I'm trying to get the Cartesian product of multiple arrays but the arrays are pretty large and I am trying to optimize memory usage. I have tried implementing a generator by using the below code but it just returns that there is a generator at a certain location. import itertools x = [[1,2],[3,4]] def iter_tools(*array): yield list(itertools.product(*array)) print(iter_tools(*x)) When I try the same code but with return instead of yield it works fine. How could I get the cartesian product by

问题 I was using sum function in pyhton, and i am clear about it's general structure sum(iterable, start) , but i am unable to get the logic behind the following code test = sum(5 for i in range(5) ) print("output: ", test) output: 25 Please can anyone describe what is happening here, basically here 5 is getting multiplied with 5, and same pattern is there for every sample input. 回答1: Your code is shorthand for: test = sum((5 for i in range(5))) The removal of extra parentheses is syntactic sugar:

问题 I was using sum function in pyhton, and i am clear about it's general structure sum(iterable, start) , but i am unable to get the logic behind the following code test = sum(5 for i in range(5) ) print("output: ", test) output: 25 Please can anyone describe what is happening here, basically here 5 is getting multiplied with 5, and same pattern is there for every sample input. 回答1: Your code is shorthand for: test = sum((5 for i in range(5))) The removal of extra parentheses is syntactic sugar:

问题 At the moment I have a little flask project that calls another python file. I'm fully aware that this way is kinda awful, and so, I want to swap it for a function call while maintaining the prints getting yelded to the website . def get_Checks(): root = request.url_root def func(): yield ("Inicio <br>") with subprocess.Popen(r"python somefile.py", stdout=subprocess.PIPE, bufsize=1, universal_newlines=True) as p: for line in p.stdout: yield (line + "<br>") return Response(func()) I've tryed to

问题 Q1 - Is the following a set() of a generator expression or a set comprehension ? (Or are they same? If so, are list & dict comprehensions also corresponding type-cast on generators?) my_set = {x for x in range(10)} Q2 - Does the evaluation consider duplicate values & then remove them by applying set() ? dup_set = {x for x in [0, 1, 2, 0, 1, 2]} Does the comprehension perform (speed-wise) better than regular for loops? Update - I tried using timeit for speed comparisons. Am not sure if I am

问题 I need to make a big test file for a sorting algorithm. For that I need to generate 10 million random strings. How do I do that? I tried using cat on /dev/urandom but it keeps going for minutes and when I look in the file, there are only around 8 pages of strings. How do I generate 10 million strings in bash? Strings should be 10 characters long. 回答1: This will not guarantee uniquness, but gives you 10 million random lines in a file. Not too fast, but ran in under 30 sec on my machine: cat

问题 I am trying to customise rails default scaffold generators. For views I can do that by simply adding files under : lib/templates/erb/scaffold/ Here I have added index.html.erb and customized, but I want to change model that is generated by this command: rails g scaffold model I have tried adding files to lib/templates/rails/model/model_generator.rb with codes like this : module Rails module Generators class ModelGenerator < NamedBase #metagenerator argument :attributes, :type => :array,

问题 I am trying to customise rails default scaffold generators. For views I can do that by simply adding files under : lib/templates/erb/scaffold/ Here I have added index.html.erb and customized, but I want to change model that is generated by this command: rails g scaffold model I have tried adding files to lib/templates/rails/model/model_generator.rb with codes like this : module Rails module Generators class ModelGenerator < NamedBase #metagenerator argument :attributes, :type => :array,

问题 I've been playing around with async generators in an attempt to make a "promise ordering" generator which takes an array of promises and yields out promises one by one in the order they resolve or reject. So something like: async function* orderProms(prom_arr) { // Make a copy so the splices don't mess it up. const proms = [...prom_arr]; while (proms.length) { // Tag each promise with it's index, so that we can remove it for the next loop. const {prom, index} = await Promise.race(proms.map(