negation

javafx 8 fxml negation

由 荒凉一梦 提交于 2019-12-13 01:58:19
问题 Using FXML with JavaFx 8. I have few ToggleButtons in toggleGroup, defined as: <ToggleGroup fx:id="operater" /> I want to disable OK button, when no operater is selected. Actually, I want to negate the disable expression in ok button: <Button disable="${operater.selectedToggle.selected}" fx:id="ok" text="OK" mnemonicParsing="false" onAction="#okClick" > I have tried with ! and with not(), but no success. Thanks. 回答1: You can use an expression binding: disable="${!operater.selectedToggle

how to get Logical Not in shell?

由 梦想的初衷 提交于 2019-12-11 14:38:58
问题 I am testing whether command exist like this: if hash pm2 2>/dev/null; then echo "already exist" else npm install --global pm2 fi but in fact I just want to do this if not exist install it fi I tried this if [ ! hash pm2 2>/dev/null ]; then npm install --global pm2 fi it is not ok 回答1: Just negate the condition in your if : if ! hash pm2 2>/dev/null; then # ^ npm install --global pm2 fi If you want to use the test command [ you have to enclose the command within a $() to get it evaluated: if

Drools Constraint object other than P is found in collection

由 妖精的绣舞 提交于 2019-12-11 09:01:41
问题 I have been trying to figure this out on and off for a really long time. I can imagine a lot of very verbose and non-droolsy ways to go about accomplishing this. However, I would like to know the best practice for dealing with a situation like this. I would like to know how to write the constraint I describe below in the drools dialect. I wish to write a constraint that deals with a collection. Let's say we have CustomType which has a field Collection. The constraint should express we want to

What does an exclamation mark in Lua do?

由 梦想与她 提交于 2019-12-11 02:25:42
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

Can I use the not operator in C++ on int values?

由 ╄→гoц情女王★ 提交于 2019-12-09 02:28:08
问题 Strange question, but someone showed me this, I was wondering can you use the not ! operator for int in C++? (its strange to me). #include <iostream> using namespace std; int main() { int a=5, b=4, c=4, d; d = !( a > b && b <= c) || a > c && !b; cout << d; system ("pause"); return 0; } 回答1: Yes. For integral types, ! returns true if the operand is zero, and false otherwise. So !b here just means b == 0 . This is a particular case where a value is converted to a bool . The !b can be viewed as

Including bean definition when a profile is NOT active

由 喜你入骨 提交于 2019-12-04 23:37:06
In my application I use several profiles to make certain beans eligible for autowiring. What I'm missing is the possibility to make a bean eligible for autowiring when a certain profile is NOT active. The best way of doing it that I thought about is like this: Let's suppose we have a list of all possible profiles, e.g. {A, B, C, D}. Profiles active for particular execution are {A, C}. What I do is I create artificial profiles for all possible profiles which are not active. In the example case I would create {not_B, not_D} profiles. The beans I want to be active based on not active profile X I

Not member rule doesn't work as expected in Prolog

由 那年仲夏 提交于 2019-12-02 18:11:50
问题 I am attempting to create a maze program in Prolog, whereby the aim is to find a route from the start of the maze to a point in the centre of the maze called m. The maze consists of squares which are connected using one of four colours: Blue, Green, Purple or Orange. The route from start to the centre follows a repeating pattern of the four colours. I have created the following code: link2(A, Colour, B) :- link(A, Colour, B). link2(A, Colour, B) :- link(B, Colour, A). changecolour(blue,green)

Not member rule doesn't work as expected in Prolog

由 和自甴很熟 提交于 2019-12-02 09:12:13
I am attempting to create a maze program in Prolog, whereby the aim is to find a route from the start of the maze to a point in the centre of the maze called m. The maze consists of squares which are connected using one of four colours: Blue, Green, Purple or Orange. The route from start to the centre follows a repeating pattern of the four colours. I have created the following code: link2(A, Colour, B) :- link(A, Colour, B). link2(A, Colour, B) :- link(B, Colour, A). changecolour(blue,green). changecolour(green,purple). changecolour(purple,orange). changecolour(orange,blue). route(A, Colour1,

Is logical negation of zero (!0) compiler dependent in C?

由 可紊 提交于 2019-12-01 21:49:29
问题 I came across an article which mentioned that the result of !0 is compiler dependent. The result can be either 1 or FF or FFFF and so on. As for C99 standard 6.5.3.3 Unary arithmetic operators, The result of the logical negation operator ! is 0 if the value of its operand compares unequal to 0, 1 if the value of its operand compares equal to 0. The result has type int. The expression !E is equivalent to (0==E). Is it really compiler dependent? 回答1: You seem to have answered you own question

Is logical negation of zero (!0) compiler dependent in C?

由 五迷三道 提交于 2019-12-01 19:49:45
I came across an article which mentioned that the result of !0 is compiler dependent. The result can be either 1 or FF or FFFF and so on. As for C99 standard 6.5.3.3 Unary arithmetic operators, The result of the logical negation operator ! is 0 if the value of its operand compares unequal to 0, 1 if the value of its operand compares equal to 0. The result has type int. The expression !E is equivalent to (0==E). Is it really compiler dependent? You seem to have answered you own question already, quoting from the standard where it specifies that the result must be 0 or 1. As such, about all I
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