logical-operators

OK so I'm a beginner with C# and I am having trouble understanding the if statement below. For this example INumber is declared as 8, dPrice is 0 and dTAX is 10. if (iNumber != 8 || iNumber != 9) { dPrice = dPrice + dTAX; } Can somebody explain why it is entering the statement and adding the 10 from dTAX to dPrice? I know changing it to && works, but why? As I understand it, it should only enter the If statement, if iNumber does not equal 8 or 9, which here it does, so it should not enter. Here are my outputs after running it through the || if statement. Inumber is: 8 dPrice was: 0 dPrice is

I'm dealing with if in R and I'm struggling with one of the typical examples: checking if it is a vowel= TRUE and FALSE otherwise. if.function <- function(char){ if (char=('a') or ('e') or ('i') or ('o') or ('u') ) { return(TRUE) } else if (char == 0){ return(FALSE) } Could someone give me a hand? I saw other examples with Python and Java, but I barely know how to use just R. char=('a') or ('e') or ('i') or ('o') or ('u') is illegal. Try isVowel <- function(char) char %in% c('a', 'e', 'i', 'o', 'u') Let's try it: isVowel('a') # [1] TRUE isVowel('b') # [1] FALSE Note that I did not use the or

I wanted to test if bitwise operations really are faster to execute than arithmetic operation. I thought they were. I wrote a small C program to test this hypothesis and to my surprise the addition takes less on average than bitwise AND operation. This is surprising to me and I cannot understand why this is happening. From what I know for addition the carry from the less significant bits should be carried to the next bits because the result depends on the carry too. It does not make sense to me that a logic operator is slower than addition. My cod is below: #include<stdio.h> #include<time.h>

In the code below: #include <stdio.h> int main() { int a = 1; int b = 1; int c = a || --b; int d = a-- && --b; printf("a = %d, b = %d, c = %d, d = %d", a, b, c, d); return 0; } i was expecting the output to be: a=0,b=1,c=1,d=0 because due to short circuiting in the line below, ie a-- returns 0 so the other part wont get executed right? int d = a-- && --b; The output is: a = 0, b = 0, c = 1, d = 0 can anyone please explain? int c = a || --b; In this line, the C standard requires the C implementation to evaluate a first and, if it is not zero, not to evaluate --b . Although -- has higher

I want to use them as a parameter to a method of my Region struct: private func combineWith(region: RegionProtocol, combine: (Bool, Bool) -> Bool) -> Region { return Region() {point in combine(self.contains(point), region.contains(point)) } } But apparently, (Bool, Bool) -> Bool) is not what && or || are. If you know, please let me know how you found out. If you "cmd-click" on the word "Swift" in the statement import Swift in Xcode and search for || then you'll find that it is declared as func ||<T : BooleanType>(lhs: T, rhs: @autoclosure () -> Bool) -> Bool The reason is the "short-circuiting

I have a function handle that operates on 2d arrays of arbitrary size: R2T = @(DL1,DL2) arrayfun(@(DL1,DL2)... 1/(fzero(@(x)fFitObj1(x)./fFitObj2(x)-... DL1./DL2,[minLim maxLim])) ... ,DL1,DL2) - C1; Here's a bottom-up breakdown of what it does: fzero(@(x)fFitObj1(x)./fFitObj2(x)-DL1./DL2,[minLim maxLim]) - This bit looks for a zero of the considered function on the interval [minLim maxLim] , where fFitObj1 and fFitObj2 are function handles available from before, C1 is some known constant and DL1, DL2 are provided. @(DL1,DL2)1/(fzero(...)) - a wrapper for fzero that allows DL1 and DL2 to be

I have two snippets of pandas code which I think should be equivalent, but the second one doesn't do what I expect. # snippet 1 data = all_data[[((np.isfinite(all_data[self.design_metric][i]) and all_data['Source'][i] == 2)) or ((np.isfinite(all_data[self.actual_metric][i]) and all_data['Source'][i] != 2)) for i in range(len(all_data))]] # snippet 2 data = all_data[(all_data['Source'] == 2 & np.isfinite(all_data[self.design_metric])) | (all_data['Source'] != 2 & np.isfinite(all_data[self.actual_metric]))] Each section (e.g. all_data['Source'] == 2 ) does what I expect on its own but it seems