comparison-operators

来源： https://stackoverflow.com/questions/40432805/how-is-true-2-implemented

来源： https://stackoverflow.com/questions/64130311/what-are-the-breaking-changes-caused-by-rewritten-comparison-operators

来源： https://stackoverflow.com/questions/64130311/what-are-the-breaking-changes-caused-by-rewritten-comparison-operators

来源： https://stackoverflow.com/questions/64130311/what-are-the-breaking-changes-caused-by-rewritten-comparison-operators

来源： https://stackoverflow.com/questions/64130311/what-are-the-breaking-changes-caused-by-rewritten-comparison-operators

问题 I have a block of code in a function that does some comparisons, namely: if customer_info['total_dls'] < min_training_actions \ or customer_info['percentage'] > train_perc_cutoff: continue elif customer_id not in test_set \ or test_set[customer_id]['total_dls'] < min_testing_actions: num_uncertain +=1 continue elif test_set[customer_id]['percentage'] <= test_perc_cutoff: num_correct +=1 else: num_incorrect +=1 Now sometimes I need to do those comparisons to be greater than, and sometimes I

问题 From what I see operator precedence makes sense in these two examples: $a = false; $b = true; $c = $a || $b; Here $c is true $a = false; $b = true; $c = $a or $b; Here $c is false I understand the reasoning behind it. However the following: $a = false; $b = true; return $a or $b; Returns true, which puzzles me. What is the reason for this? 回答1: or has lower precedence than = , so this: $c = $a or $b; Becomes this: ($c = $a) or $b; But this doesn't make sense: (return $a) or $b; So you get

问题 I see that a similar question exists for JSP but I don't see a StackOverflow question for Fortran. The question is: what is the difference between the comparison operators " .eq. " and " == " in Fortran? Note that since I use multiple versions of Fortran (77 and 90 mostly) I'd be interested in knowing if this has changed across versions or at least to what version your answer is in regards to. Also, since I've only been able to find tutorials on google, it would be great if you could

问题 I see that a similar question exists for JSP but I don't see a StackOverflow question for Fortran. The question is: what is the difference between the comparison operators " .eq. " and " == " in Fortran? Note that since I use multiple versions of Fortran (77 and 90 mostly) I'd be interested in knowing if this has changed across versions or at least to what version your answer is in regards to. Also, since I've only been able to find tutorials on google, it would be great if you could

问题 According to cppreference, std::type_info::operator!= gets removed with C++20, however, std::type_info::operator== apparently remains. What's the reasoning behind? I might agree on comparing for inequality being meaningless, but then comparing for equality would be just as meaningless as well, wouldn't it? Similarly, operator!= of many other standard library types, including containers such as std::unordered_map::operator!= and std::unordered_set::operator!= will be removed in C++20 according