boolean-operations

问题 Assuming you have a multiple boolean fields within a common category, which database storage method is more efficient for both speed and processing (for both MySQL and PHP)? For example, if choosing a car you may have a category "options" with the following selections: (GPS,Tow package,Radar,Powersteering). All options are boolean fields, which must be answered, and must be TRUE or FALSE . Is it better to set up a table with each field: CREATE TABLE IF NOT EXISTS `manycars` ( `vin` int(10)

问题 I have two numpy arrays of the same shape. The elements in the arrays are random integers from [0,N]. I need to check which (if any) of the elements in the same position in the arrays are equal. The output I need are the positions of the same elements. mock code: A=np.array([0,1]) B=np.array([1,0]) C=np.array([1,1]) np.any_elemenwise(A,B) np.any_elemenwise(A,C) np.any_elemenwise(A,A) desired output: [] [1] [0,1] I can write a loop going through all of the elements one by one, but I assume

问题 please help me with simplifying this one. I am a bit new to these.. (A'BC') + (A'B'C) + (A'BC) + (AB'C) the book i use shows and answer, which is, Answer = A'B + B'C I tried simplifying, but I get stucked with two eXors, my simplification so far goes like this... (A'BC') + (A'B'C) + (A'BC) + (AB'C) A (BC' + B'C) + C (A'B + AB') This doesn't seem to be a write way, Please someone help me simplify this, and please show step by step, as I am sort of new.. Also I don't get how to simplify eXor

问题 I have a function where I'm calculating two float values with a conditional if statement for the return values shown below: # The function inputs are 2 lists of floats def math(list1,list2): value1=math(...) value2=more_math(...) z=value2-value1 if np.any(z>0): return value1 elif z<0: return value2 Initially, I ran into the title error. I have tried using np.any() and np.all() as suggested by the error and questions here with no luck. I am looking for a method to explicitly analyze each

问题 I have nested lists of truth values representing SAT forumlas, like this: [[[0, True, False], [0, True, False], [0, True, 1]], [[0, True, True], [2, True, True], [3, False, True]], [[1, False, False], [1, False, False], [3, False, True]]] representing ([x0=0] + [x0=0] + [x0=1]) * ([x0=1] + [x1=1] + [-x2=1]) * ([-x3=0] + [-x3=0] + [-x2=1]) I would like to calculate the truth value of the whole formula. First step would be adding up the truth values of the literals in each clause. like this:

问题 From a sequence of TRUEs and falses, I wanted to make a function that returns TRUE whether there is a series of at least n1 TRUEs somewhere in the sequence. Here is that function: fun_1 = function(TFvec, n1){ nbT = 0 solution = -1 for (i in 1:length(x)){ if (x[i]){ nbT = nbT + 1 if (nbT == n1){ return(T) break } } else { nbT = 0 } } return (F) } Test: x = c(T,F,T,T,F,F,T,T,T,F,F,T,F,F) fun_1(x,3) # TRUE fun_1(x,4) # FALSE Then, I needed a function that returns TRUE if in a given list boolean

问题 I have a bunch of methods that all return a bool. If one method returns false then there is no value in calling the following methods, especially as some of them are 'expensive' operations. Which is the more efficient? bool result = method1(); if (result) result = method2(); if (result) result = method3(); return result; or return method1() && method2() && method3(); As I understand it, the 2nd form should stop evaluating as soon as one of the methods returns false, right? 回答1: Yes you are

问题 I've bool arrays of sizes : 32, 48, 64 (each boolean represents a bit). how can I convert them to a number with a good performance( int, unsigned int, double48, double64)? for example : bool ar[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,1} int num = bitArrayToInt32(ar,32);// num = 65 回答1: O(n): int bitArrayToInt32(bool arr[], int count) { int ret = 0; int tmp; for (int i = 0; i < count; i++) { tmp = arr[i]; ret |= tmp << (count - i - 1); } return ret; } int main() { bool ar[]

问题 I’m trying to figure out what the differences are between the above-mentioned routines, and if statements like say $y.Bool; say $y.so; say ? $y; say so $y; would ever produce a different result. So far the only difference that is apparent to me is that ? has a higher precedence than so . .Bool and .so seem to be completely synonymous. Is that correct and (practically speaking) the full story? 回答1: What I've done to answer your question is to spelunk the Rakudo compiler source code. As you

问题 The following code doesn't compile #include <vector> int main() { std::vector<bool> enable(10); enable[0] |= true; return 0; } giving the error no match for ‘operator|=’ (operand types are ‘std::vector<bool>::reference {aka std::_Bit_reference}’ and ‘bool’) In my real life code I have a bit field with values I want to |= with the result of a function. There are easy way to express the same idea, but is there any good reason for such an operator not to be available ? 回答1: The main reason would