logic

问题 This code: a = {'sd':{},'sdd':'','sadfas':None,'sadfa':'dsf'} a = dict((k, v) for k, v in a.iteritems() if v is not '' or v != {} or v is not None) print a prints: {'sdd': '', 'sadfas': None, 'sadfa': 'dsf', 'sd': {}} However, it does not remove all the type of values from dict which i need to remove. Why is that ? These values are removed if i do: a = {'sd':{},'sdd':'','sadfas':None,'sadfa':'dsf'} a=dict((k, v) for k, v in a.iteritems() if v is not '') a=dict((k, v) for k, v in a.iteritems()

问题 Not sure why this problem is occurring, but for some reason I'm getting the wrong output. What I'm trying to do is take an existing average of ratings and generate a new one. The case I'm currently solving is when a user who has already been calculated in the average needs their value changed. For example: User A rates at 5 stars User B rates at 3 stars User C rates at 5 star Current average stars is: 13/3 or 4.333 Now if user B changes their rating, and I don't want to go cycling through all

问题 Not sure why this problem is occurring, but for some reason I'm getting the wrong output. What I'm trying to do is take an existing average of ratings and generate a new one. The case I'm currently solving is when a user who has already been calculated in the average needs their value changed. For example: User A rates at 5 stars User B rates at 3 stars User C rates at 5 star Current average stars is: 13/3 or 4.333 Now if user B changes their rating, and I don't want to go cycling through all

问题 I have two DataFrames where each column contain True/False statements. I am looking for a way to test all possible combinations and find out where "True" for each row in df1 also is "True" in the corresponding row in df2. In reference to the data below, the logic would be something like this: For each row, starting in column "Main1", test if row is equal to True and if row in column "Sub1" also is True. Next, test if row in "Main1" is equal to true and if rows in column "Sub1" is True and

问题 I have a list of strings along with conditions that determine how they should be sorted. The conditions can be simplified to the form, X before Y or X after Y . However, one (or more) of the conditions contradict the rest. Given a bunch of such conditions, I need to determine which conditions contradict the most other conditions so that I can eliminate the fewest conditions necessary to make them consistent with each other. Once this is done, I will be able to reverse-engineer the original

问题 I have a list of strings along with conditions that determine how they should be sorted. The conditions can be simplified to the form, X before Y or X after Y . However, one (or more) of the conditions contradict the rest. Given a bunch of such conditions, I need to determine which conditions contradict the most other conditions so that I can eliminate the fewest conditions necessary to make them consistent with each other. Once this is done, I will be able to reverse-engineer the original

问题 Here's a snippet of code which i am trying to use to retrieve all the links from a website given the URL of a homepage. import requests from BeautifulSoup import BeautifulSoup url = "https://www.udacity.com" response = requests.get(url) page = str(BeautifulSoup(response.content)) def getURL(page): start_link = page.find("a href") if start_link == -1: return None, 0 start_quote = page.find('"', start_link) end_quote = page.find('"', start_quote + 1) url = page[start_quote + 1: end_quote]

问题 I am currently writing a Minesweeper game. It was going fine until I encountered the problem with exposing multiple tiles in one click. Whenever I click something, it never shows mines (like it's supposed to) but only ever works its way down, to the left, and to the right. I made it so it prints its direction, and it thinks down is right, etc. I have never encountered a left. Here is my code: from tkinter import * from random import * root = Tk() root.resizable(0, 0) root.title("Minesweeper")

问题 I'm developing a stock inventory system using PHP, Mysql. This system have purchase module to add/update/increase quantity and expire date of products & sale module to decrease/out the quantity of products. Now what is creating confusion to me and what is my real question is that Suppose we have PRODUCT A1 in our stock with quantity 20 and the price of PRODUCT A1 was $15 when we purchase it. Now we want to stock this product more for example we want to buy 100 more items of PRODUCT A1 but now

问题 Is there a software package (preferable an application, not library) that creates Reduced Ordered Binary Decision Diagrams (ROBDDs) from a given truth table (in some text format)? 回答1: You can also try this: http://formal.cs.utah.edu:8080/pbl/BDD.php It is the best tool for BDDs I used so far. 回答2: With any BDD library you can do what you want. Of course, you must write a piece of code by yourself. If you are looking for a lightweight tool, I often use an applet like this to have a quick look