boolean-logic

Any good boolean expression simplifiers out there? [closed]

由 与世无争的帅哥 提交于 2019-11-26 23:54:07
问题 Closed. This question is off-topic. It is not currently accepting answers. Want to improve this question? Update the question so it's on-topic for Stack Overflow. Closed 4 years ago . I was refactoring old code and encountered several IF conditions that were way too complex and long and I'm certain they can be simplified. My guess is that those conditions grew so much because of later modifications. Anyway, I was wondering if any of you know of a good online simplifier I can use. I'm not

How to understand De Morgan Laws Boolean Expression

由 爷，独闯天下 提交于 2019-11-26 23:36:53
问题 I got screwed when trying to understand this expression. I've thought several times but I cant get the meaning. ! (p || q) is equivalent to !p && !q For this one, somehow I can comprehend a little bit. My understanding is " Not (p q) = not p and not q" which is understandable ! (p && q) is equivalent to !p || !q For the second, I'm totally got screwed. How come My understanding is " Not (p q) = Not p or Not q " . How come and and or can be equivalent each other? as for the rule in the truth

why are Javascript negative numbers not always true or false?

由 扶醉桌前 提交于 2019-11-26 18:10:18
问题 -1 == true; //false -1 == false //false -1 ? true : false; //true Can anyone explain the above output? I know I could work round this by comparing to 0 but I'm interested. I'd expect at least one of the sloppy equals statements to be true as they do implicit type conversion, and I certainly didn't expect the ternary to come up with a totally different result. 回答1: In the first two cases, the boolean is cast to a number - 1 for true and 0 for false. In the final case, it is a number that is

Should I always use the AndAlso and OrElse operators?

由 送分小仙女□ 提交于 2019-11-26 16:48:35
问题 Is there ever a circumstance in which I would not want to use the AndAlso operator rather than the And operator? …or in which I would not want to use the OrElse operator rather than the Or operator? 回答1: From MSDN: Short-Circuiting Trade-Offs Short-circuiting can improve performance by not evaluating an expression that cannot alter the result of the logical operation. However, if that expression performs additional actions, short-circuiting skips those actions. For example, if the expression

How can I obtain the element-wise logical NOT of a pandas Series?

由 烈酒焚心 提交于 2019-11-26 15:56:33
I have a pandas Series object containing boolean values. How can I get a series containing the logical NOT of each value? For example, consider a series containing: True True True False The series I'd like to get would contain: False False False True This seems like it should be reasonably simple, but apparently I've misplaced my mojo =( To invert a boolean Series, use ~s : In [7]: s = pd.Series([True, True, False, True]) In [8]: ~s Out[8]: 0 False 1 False 2 True 3 False dtype: bool Using Python2.7, NumPy 1.8.0, Pandas 0.13.1: In [119]: s = pd.Series([True, True, False, True]*10000) In [10]:

Boolean Implication

由 拈花ヽ惹草 提交于 2019-11-26 15:56:14
问题 I need some help with this Boolean Implication. Can someone explain how this works in simple terms: A implies B = B + A' (if A then B). Also equivalent to A >= B 回答1: Boolean implication A implies B simply means "if A is true, then B must be true". This implies (pun intended) that if A isn't true, then B can be anything. Thus: False implies False -> True False implies True -> True True implies False -> False True implies True -> True This can also be read as (not A) or B - i.e. "either A is

Why TRUE == “TRUE” is TRUE in R?

由 ￣綄美尐妖づ 提交于 2019-11-26 13:47:42
问题 Why TRUE == "TRUE" is TRUE in R? Is there any equivalent for === in R? Update: These are all returning FALSE : TRUE == "True" TRUE == "true" TRUE == "T" The only TRUE value is TRUE == "TRUE" . In case of checking with identical() everything works fine. Second Update: By === operator I meant the process of checking the Value and the Data Type of a variable . In this case I assumed that the == operator will only compare the Values of variables, not their Data Type as well. 回答1: According to the

Element-wise logical OR in Pandas

由 核能气质少年 提交于 2019-11-26 12:28:47
问题 I would like the element-wise logical OR operator. I know \"or\" itself is not what I am looking for. I am aware that AND corresponds to & and NOT, ~ . But what about OR? 回答1: The corresponding operator is | : df[(df < 3) | (df == 5)] would elementwise check if value is less than 3 or equal to 5. If you need a function to do this, we have np.logical_or. For two conditions, you can use df[np.logical_or(df<3, df==5)] Or, for multiple conditions use the logical_or.reduce , df[np.logical_or

Why does (0 < 5 < 3) return true?

由 ε祈祈猫儿з 提交于 2019-11-26 11:36:20
I was playing around in jsfiddle.net and I'm curious as to why this returns true? if(0 < 5 < 3) { alert("True"); } So does this: if(0 < 5 < 2) { alert("True"); } But this doesn't: if(0 < 5 < 1) { alert("True"); } Is this quirk ever useful? Order of operations causes (0 < 5 < 3) to be interpreted in javascript as ((0 < 5) < 3) which produces (true < 3) and true is counted as 1, causing it to return true. This is also why (0 < 5 < 1) returns false, (0 < 5) returns true, which is interpreted as 1 , resulting in (1 < 1) . My guess is because 0 < 5 is true, and true < 3 gets cast to 1 < 3 which is

Why does “one” < 2 equal FALSE in R?

由 醉酒当歌 提交于 2019-11-26 11:35:45
问题 I\'m reading Hadley Wickham\'s Advanced R section on coercion, and I can\'t understand the result of this comparison: \"one\" < 2 # [1] FALSE I\'m assuming that R coerces 2 to a character, but I don\'t understand why R returns FALSE instead of returning an error. This is especially puzzling to me since -1 < \"one\" # TRUE So my question is two-fold: first, why this answer, and second, is there a way of seeing how R converts the individual elements within a logical vector like these examples?
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