logic

问题 Often in my code I need to check whether the state of x amount of bools are all true OR all bools are false. So I do: BOOL first, second, third; if((first && second && third) || (!first && !second && !third)) //do something Being a lazy programmer, I want to know if there is some mathematical shorthand for this kind of query, instead of having to type out this whole thing every time? 回答1: The shorthand for all bools the same is testing for (pairwise) equality: (first==second && second==third)

问题 I want to see if a variable is between a range of values, for example if x is between 20 and 30 return true. What's the quickest way to do this (with any C based language)? It can obviously be done with a for loop: function inRange(x, lowerbound, upperbound) { for(i = lowerbound; i < upperbound; i++) { if(x == i) return TRUE; else return FALSE; } } //in the program if(inRange(x, 20, 30)) //do stuff but it's awful tedious to do if(inRange(x, 20, 30)) is there simpler logic than this that doesn

问题 Maybe this is just obvious to everyone but can someone explain where XOR (or Exclusive-OR) got its name from? What does the word Exclusive really mean? Not that it matters, but its just stuck in my head since morning. OR: 0 0 0 0 1 1 1 0 1 1 1 1 XOR: 0 0 0 0 1 1 1 0 1 1 1 0 Is it "exclusively 0 for inputs 1,1", "special version of OR" or something else? 回答1: XOR is an "exclusive OR" because it only returns a "true" value of 1 if the two values are exclusive, i.e. they are both different. 回答2:

问题 I have a dictionary: 'Consulting': {'Deloitte', 'EY', 'KPMG', 'PwC'}, 'Education': {'.edu', 'College', 'University'}, 'Government':{'state','.gov','city'}, 'Corporate':{'corpor','consumer','care'}, ...... etc. I have a dataframe: Sno Text column1 column2 ...... 1 Deloitte.com 2 Texas.gov 3 smi@EY.com 4 UTD.edu 5 rapper@corporate.com ..... etc. I want to use the dictionary to categorize the dataframe and build a column Category, like this: Sno Text Category column1 column2 ...... 1 Deloitte

问题 I am new to the topic of propositional logic and boolean expressions. So this is why I need help. Here is my problem: In the car industry you have thousand of different variants of components available to choose from when you buy a car. Not every component is combinable, so for each car there exist a lot of rules that are expressed in propositional logic. In my case each car has between 2000 and 4000 rules. They look like this: A → B ∨ C ∨ D C → ¬F F ∧ G → D ... where "∧" = "and" / "∨" = "or"

问题 I am programming my first real PHP website and am wondering how to make my code more readable to myself. The reference book I am using is PHP and MySQL Web Development 4th ed. The aforementioned book gives three approaches to separating logic and content: include files function or class API template system I haven't chosen any of these yet, as wrapping my brains around these concepts is taking some time. However, my code has become some hybrid of the first two as I am just copy-pasting away

问题 I have complex logical expression that look like this: ((((!((cond1) || (cond2) || (cond3)) && (cond4))) && (cond5)) <= (((cond6) || (cond7) || (cond8)) || (cond9))) Each line has several dozens of expressions. The allowed logical signs are || , && , ! and <= . <= means leads, as in a <= b means that b leads to a. I need to go over those statements and check the conditions, since some of them are no longer valid. I want to be able to parse it to a tree, then check each of it leafs (where each

问题 I have been finding some articles and post which suggest not to use the regular expression to validate user data. I am not sure of all the things but i usually find it in case of email address verification. So i want to be clear whether using regular expression for validating user input is good or not? if it is good then what is bad with it for validating email address? Edit: So can we say that for basic primary validation of data types we can use regex and it is good and for full validation

问题 This is the smallest runnable SSCCE ,of my project, that I could implement to show you. I've read that calling the game logic from the Event Dispacth Thread is a bad practice , how can I separate them, because as you can see update() and repaint() are related into loop and how can I separate code in a pretty way, I'm getting in trouble with this, trying to find out how to do it. I've posted a similar question regarding and I got an answer,that says to use a Swing Timer,but i have huge task to

问题 I've encountered some obj-c code and I'm wondering if there's a way to simplify it: #if ( A && !(B || C)) || ( B || C ) is this the same as? #if ( A || B || C ) If not, is there another way to formulate it that would be easier to read? [edit] I tried the truth table before asking the question, but thought I had to be missing something because I doubted that Foundation.framework/Foundation.h would employ this more complex form. Is there a good reason for it? Here's the original code (from