logical-operators

问题 This question is a follow-up question on Can the C compiler optimizer violate short-circuiting and reorder memory accesses for operands in a logical-AND expression?. Consider the following code. if (*p && *q) { /* do something */ } Now as per the discussion at Can the C compiler optimizer violate short-circuiting and reorder memory accesses for operands in a logical-AND expression? (especially David Schwartz comment and answer) it is possible for the optimizer of a standard-conformant C

问题 I need to make a formula in Excel which sums the values of the previous 6 cells. The complicated part is that if there are only null values, the total should be a hyphen: "-". I got this to work, but then realized there are two possible null values: hyphen and blank. Here is the formula I created for the hyphen as the null value. It worked how I wanted. But then several cells came out with a "0" since they were summing both types of null values. =IF(OR(K3 ="-",L3 ="-", M3 ="-", N3 ="-",O3 ="-

问题 I am trying to make a program generating random numbers until it finds a predefined set of numbers (eg. if I had a set of my 5 favourite numbers, how many times would I need to play for the computer to randomly find the same numbers). I have written a simple program but don't understand the outcome which seems to be slightly unrelated to what I expected, for example the outcome does not necessarily contain all of the predefined numbers sometimes it does (and even that doesn't stop the loop

问题 I'm trying to do the following: Check the cell for N/A or No ; if it has either of these then it should output N/A or No Check the cell for either £ or € or Yes ; If it has one of these then it would continue to step 3. If it has $ then it should repeat the same input as the output. Extract currency from cell using: REGEXEXTRACT(A1, "\$\d+") or REGEXEXTRACT(A1, "\£\d+") (I assume that's the best way) Convert it to $ USD using GoogleFinance("CURRENCY:EURUSD") or GoogleFinance("CURRENCY:GBPUSD"

问题 If you google for PowerShell Eqv you currently will find the VBScript-to-Windows PowerShell Conversion Guide on top of the list. Yet the answer is much of technical help: Eqv Operator Definition: Performs a logical equivalence on two expressions. No doubt Eqv has its uses; we’re just not sure if it has any practical uses. Although there might be a Windows PowerShell equivalent we have to be honest: we didn’t look real hard for one. In fact, I used the Eqv operator (also written as: A↔B ) a

问题 Question is in the title, really. I saw someone use this earlier and I didn't know what the ! was used for. local lowestIndex = 0; local lowestValue = false; for k, v in ipairs(playerElement) do if !lowestValue or v.value < lowestValue then lowestIndex = k; lowestValue = v; end end 回答1: As others have said, ! normally has no function in Lua, and the code you posted would not normally be valid. However, it's quite trivial to extend Lua's parser to allow for custom syntax, and it's not unheard

问题 cond && cond op cond op can be && or || Qn- For short circuit ( && ) operator if the first cond is false then right part (whole) is not evaluated or just the second cond after && is not evaluated Also why the result of following two expressions different? (2 > 3 && 5 < 2 || 3 > 2) => True (2 > 3 && 5 < 2 | 3 > 2) => False Can't we use short circuit operator and standard operators in a single expression...? 回答1: The results are different because | and || have different precedence. Specifically

问题 I am new to scala and was trying a few basic operations to get a hang of the language. I am trying to use the logical operators. For example : val a2 = 0x01&0xFF println(!a2) I want to negate the value of a2 and then print it out. But it gives me an error saying value unary_! is not a member of Int I am not sure on how do I use the NOt operator. Could somebody help me? 回答1: Use the bitwise not operator ~ . val a2 = 0x01&0xFF println(~a2) Check here for reference. Of course, this is assuming

问题 If I needed to perform a bitwise AND operation of two 16bit inputs and obtain a 16bit output in VHDL, would I be able to just AND the two inputs and store the result as the output vector? Or would I need to loop through each bit of the inputs, AND them, then store the result in the output vector? Would this work similarly for operations like or and xor? 回答1: The "and" operator is overloaded in the std_logic_1164 package for std_logic , std_ulogic , std_logic_vector , and std_ulogic_vector

问题 Problem I have data on two measures for four individuals each in a wide format. The measures are x and y and the individuals are A, B, C, D . The data frame looks like this d <- data.frame(matrix(sample(1:100, 40, replace = F), ncol = 8)) colnames(d) <- paste(rep(c("x.", "y."),each = 4), rep(LETTERS[1:4], 2), sep ="") d x.A x.B x.C x.D y.A y.B y.C y.D 1 56 65 42 96 100 76 39 26 2 19 93 94 75 63 78 5 44 3 22 57 15 62 2 29 89 79 4 49 13 95 97 85 81 60 37 5 45 38 24 91 23 82 83 72 Now, would I