random

问题 running gradle build on an android project or module yields the following lint report entry: Potentially insecure random numbers on Android 4.3 and older. Read https://android-developers.blogspot.com/2013/08/some-securerandom-thoughts.html for more info. This provides an easy to implement patch for said issue. But I'm wondering if it needs to be applied, given that it's 5 years old, or can this be ignored? Thanks 回答1: That depends on whether your app must support Android versions 4.3 and

问题 I'm trying to make a Bingo ticket (Housie) generator, but I've got some problems. Normally, each row contains five numbers and four blank spaces randomly distributed along the row. Numbers are apportioned by column (1–9, 10–19, 20–29, 30–39, 40–49, 50–59, 60–69, 70–79, and 80–90). My generator looks like this: As you can see, I can't manage to have 5 numbers per row. My code is the following (I'm using the RandomPlus class): package com.demstra.Ticket { import flash.display.MovieClip; public

问题 To reproduce : # Use scipy to create random number for f(x) = 2x when x in [0,1] and 0, otherwise from scipy.stats import rv_continuous class custom_rv(rv_continuous): "custom distribution" def _pdf(self, x): if x >= 0.0 and x <=1.0: return 2*x else: return 0.0 rv = custom_rv(name='2x') from scipy.integrate import quad print(quad(rv._pdf, -10.0, 10.0)) print(quad(rv._pdf, -5.0, 5.0)) print(quad(rv._pdf, -np.inf, np.inf)) Output : (0.0, 0.0) # for [-10,10] (1.0, 1.1102230246251565e-15) # for [

问题 I am somewhat confused about how to use numpy.random to generate random values from a give distribution, say, binomial. I thought it would be import numpy as np np.random.binomial(10, 0.3, 5) However, NumPy reference page shows something like from numpy.random import default_rng rg = default_rng() rg.binomial(10, 0.3, 5) Both seem to be working well. Which one is the correct or better way? What is the difference if there is any? 回答1: The first block of code uses a numpy.random.* function.

问题 I am trying to write an OpenMP code in which each thread will work on big arrays of uniformly distributed random numbers between 0 and 1. Each thread needs to have different and independent random number distributions. In addition, the random number distributions need to be different every time the code is called. This is what I am using right now. Does this always guarantee each thread has its own/different random number sequences? Will the sequences be different every time the code is

问题 I am trying to write an OpenMP code in which each thread will work on big arrays of uniformly distributed random numbers between 0 and 1. Each thread needs to have different and independent random number distributions. In addition, the random number distributions need to be different every time the code is called. This is what I am using right now. Does this always guarantee each thread has its own/different random number sequences? Will the sequences be different every time the code is

问题 I have a table of movies, I want to be able to query the database and get a randomized list of movies, but also I don't want it to return all movies available so I'm using LIMIT and OFFSET . The problem is when I'm doing something like this: SELECT * FROM Movie ORDER BY RANDOM() LIMIT 50 OFFSET 0 and then when querying for the next page with LIMIT 50 OFFSET 50 the RANDOM seed changes and so it's possible for rows from the first page to be included in the second page, which is not the desired

问题 Consider the following functions: def a(): print "a" def b(): print "b" Is there a way to pick a function to run randomly? I tried using: random.choice([a(),b()]) but it returns both functions, I just want it to return one function. 回答1: Only call the selected function, not both of them: random.choice([a,b])() Below is a demonstration: >>> import random >>> def a(): ... print "a" ... >>> def b(): ... print "b" ... >>> random.choice([a,b])() a >>> random.choice([a,b])() b >>> Your old code

问题 Consider the following functions: def a(): print "a" def b(): print "b" Is there a way to pick a function to run randomly? I tried using: random.choice([a(),b()]) but it returns both functions, I just want it to return one function. 回答1: Only call the selected function, not both of them: random.choice([a,b])() Below is a demonstration: >>> import random >>> def a(): ... print "a" ... >>> def b(): ... print "b" ... >>> random.choice([a,b])() a >>> random.choice([a,b])() b >>> Your old code

问题 The problem is that I need to generate a random integer between 0 and 999 (for investigation of a mathematical conjecture). All of the values need to have the same probability of coming up. I have tried rand() , but with RAND_MAX being 32767 (on my compiler) this means that just taking rand() % 1000 leads to the first 1–767 being significantly more likely to come up (and that's assuming that all possibilities have the same probability in rand() in the first place). I'm using Windows so /dev