boolean-operations

问题 The If statement and any other boolean comparison is smart enought to stop at first FALSE value when evaluating A and B and C and D and at first TRUE value when evaluating A or B or C or D . What is the name of this behavior? Is this a compiler optimization? If so, there is a way to disable it with some compiler directive? 回答1: This is called 'boolean short-circuit evaluation', a form of 'lazy evaluation'. You can tell the compiler either to use or not to use this feature using compiler

问题 The If statement and any other boolean comparison is smart enought to stop at first FALSE value when evaluating A and B and C and D and at first TRUE value when evaluating A or B or C or D . What is the name of this behavior? Is this a compiler optimization? If so, there is a way to disable it with some compiler directive? 回答1: This is called 'boolean short-circuit evaluation', a form of 'lazy evaluation'. You can tell the compiler either to use or not to use this feature using compiler

问题 This question already has answers here : 'and' (boolean) vs '&' (bitwise) - Why difference in behavior with lists vs numpy arrays? (8 answers) Closed 5 years ago . Is there any difference in the logic or performance of using the word and vs. the & symbol in Python? 回答1: and is a Boolean operator. It treats both arguments as Boolean values, returning the first if it's falsy, otherwise the second. Note that if the first is falsy, then the second argument isn't even computed at all, which is

问题 I am currently in the course of learning Python 2.7 and have come across the Equality and Boolean operators My question is: Why False and 1 is False but True and 1 is 1 Likewise, False or 1 is 1 but True or 1 is True Can someone kindly explain why this is happening Many thanks 回答1: and returns the first 'falsy' (False, zero, empty string or list, etc.) value it sees, or the final value if none were falsy. Further values are not even evaluated, since they can't change the result. or likewise

问题 I have an STL of a gyroid & I want to crop it with a sphere (previous question) Now I have the data represented in the correct manner but whenever I do a Boolean operation on my 2 objects I get an empty result. import vtk colors = vtk.vtkNamedColors() file_name = 'gyroid.stl' # Load poly from STL reader = vtk.vtkSTLReader() reader.SetFileName(file_name) reader.Update() polyData = reader.GetOutput() # Centre of poly x = (polyData.GetBounds()[1] - polyData.GetBounds()[0]) / 2.0 y = (polyData

问题 I have an STL of a gyroid & I want to crop it with a sphere (previous question) Now I have the data represented in the correct manner but whenever I do a Boolean operation on my 2 objects I get an empty result. import vtk colors = vtk.vtkNamedColors() file_name = 'gyroid.stl' # Load poly from STL reader = vtk.vtkSTLReader() reader.SetFileName(file_name) reader.Update() polyData = reader.GetOutput() # Centre of poly x = (polyData.GetBounds()[1] - polyData.GetBounds()[0]) / 2.0 y = (polyData

问题 I have an STL of a gyroid & I want to crop it with a sphere (previous question) Now I have the data represented in the correct manner but whenever I do a Boolean operation on my 2 objects I get an empty result. import vtk colors = vtk.vtkNamedColors() file_name = 'gyroid.stl' # Load poly from STL reader = vtk.vtkSTLReader() reader.SetFileName(file_name) reader.Update() polyData = reader.GetOutput() # Centre of poly x = (polyData.GetBounds()[1] - polyData.GetBounds()[0]) / 2.0 y = (polyData

问题 For example, if you have n lists of bools of the same length, then elementwise boolean AND should return another list of that length that has True in those positions where all the input lists have True, and False everywhere else. It's pretty easy to write, i just would prefer to use a builtin if one exists (for the sake of standardization/readability). Here's an implementation of elementwise AND: def eAnd(*args): return [all(tuple) for tuple in zip(*args)] example usage: >>> eAnd([True, False

问题 I am trying to write a query to pull data from my Neo4J database. Lets say there are five conditions that determine whether or not I want to pull _____ from my database: A, B, C, D, and E. The boolean expression which determines this is: A && B && (C || D || E) From scouring the web, I cannot find any information about an order of operations that Neo4J AND and OR queries abide by (AND usually precedes OR), but from my observations they seem like they execute sequentially. Since there is no

问题 This question already has answers here : Weird behaviour of NOT (3 answers) Closed 5 months ago . This has me utterly baffled. Sub testChangeBoolean() Dim X As Boolean ' default value is False X = True ' X is now True X = Not X ' X is back to False End Sub But I'm trying to toggle the .FitText property in a table cell (in Word). .FitText starts as True. If I assign it to X: Sub testChangeBoolean() Dim X As Boolean ' again, default is False X = Selection.Cells(1).FitText ' does set X to True X