My codes looks like this:
_user.role >= level if _user?
I tried the codes below, but found it didn't work
_user?.role >= level
Does anyone have ideas about write shorter codes for this?
What do you want in case _user is null? If you want nothing (undefined), then use the first code. If you want false, then use second one. Or want another value from the expression?
Related
The following works in Flutter, however, I have an IDE warning to avoid "unnecessary statements." I'm sure many will pipe in citing the Latin root of three in ternary and other critiques, and I appreciate that kind of fun dialog, I really do, however, sometimes in a nested sequence, this stuff comes up..not just in the simple example I'm giving.
As I said, the below works, I just get an Android Studio IDE warning. I'd probably be better off to correct it if there is something more appropriate when using a ternary operator
x == 4 ? doSomething() : null
Couldn't find any documentation on this.
Just don't use ternary.
if( x == 4 ) doSomething()
Applies to List and Map as well.
Android Studio at least has updated this check and it is now allowed without warnings. It was a common logic in validators at least, and someone saw the light. So the correct answer was: It's perfectly reasonable and good code. (at least in my opinion!)
The ternary operator is not built for such a situation. It should use where we have at least two options
condition ? doThisIfTrue() : doThisIfFalse()
If we have only one option, then simply use if
if ( condition ) {
doThis
}
The code that you wrote, is not wrong either, but that is not use of ternary operator.
Does specman have something like lex_lt(s1,s2) methods? (i.e. compare strings by lexicographical order). If not, is there a recommended way to achieve the same?
It seems that there isn't. You can do 2 things here. You can either implement your own strcmp() style function in e and use that directly, or you can integrate Specman with a C file that wraps strcmp() in function that can be called from your e code. Have a look at the Specman Integrator's Guide section in the product manual for details on how to do this.
As far as I know, we don’t have something pre-defined for this.
But it can be done, for example, in the following ugly way:
if {s1;s2}.sort(it)[0] == s1 …. // if it’s TRUE, then s1 is less that s2, otherwise not
Of course, as Tudor suggested, the best way will be to define C routine to wrap strcmp().
I'm migrating my karma-ng-scenario tests suite to protractor. I would like to do something like
// karma-ng-scenario
expect(element('legend').text()).not().toBe("LOGIN_CONNECT");
in the protractor way. But it seems there isn't a not() function.
I'm using angular-translate to bind the LONGIN_CONNECT string into multiple languages and I want to test if the string is translated.
More globally, is there a a way test if something is different ? ... don't have a class, don't exists on the page, is not selected, ...
It is definitely worth looking at the API docs. I have these open pretty much all the time.
There are lots of Web Driver functions you can use like isEnabled(), isDisplayed(), isSelected() etc. Protractor uses Jasmine syntax so you can use '.toBe(false)' to assert things are false.
To check for classes, you can do something like:
expect(myElement.getAttribute('class')).toContain('my-class-name');
To compare strings and assert that they do NOT match you could use .not. Jasmine docs
say:
Every matcher's criteria can be inverted by prepending .not:
expect(x).not.toEqual(y); compares objects or primitives x and y and
passes if they are not equivalent
You can use something like:
expect(model.getText()).not.toContain('abcdef');
There is a .not property nowadays.
I'm using the following to check for NOT matching:
expect(element('legend').text() === "LOGIN_CONNECT").toBe(false);
Let's say I get two instances in my code and I don't know their types. How to check it?
If in Java, I can use this code:
a.getClass() == b.getClass()
But in Dart, I can't find similar methods. Although there is the dart:mirrors providing reflect(instance) function, which may let me do it, but I'm not sure if that's a correct solution since it looks complicated.
a.runtimeType == b.runtimeType
I think dart:mirrors (reflection) API helps you. Look at this page :
http://blog.dartwatch.com/2012/06/dartmirrors-reflection-api-is-on-way.html
Also you can look this question(with runtime solution)
How do I get the qualified name from a Type instance, in Dart?
if you want to compare a and b you can use
if(a.runtimeType == b.runtimeType);
but if you want to confirm that a is the type you want you need to do this
if(a.runtimeType.toString()=="DivElement");//a is a div for instance
because runtimeType's value is not a string
I am trying to handle a simple case where i could be getting an object, or a dictionary. So i am either going to get a object like:
obj.fields.nick
or its going to be a dictionary like
obj['nick']
I was wondering if there was a simpler way to do the following:
value = (eval("obj.fields." + field[1]) if obj?.fields ) ? eval("obj['#{field[1]}']")
I was hoping to do something like:
value = (obj?.fields?."#{field[1]}" ) ? eval("obj['#{field[1]}']")
But if that worked I wouldn't be writing this post...
I am basically looking for a way to execute a string as part of the if
value = obj.fields?[field] ? obj[field]
# or
value = (obj.fields ? obj)[field]
This is the same as
if obj.fields?
obj.fields[field]
else
obj[field]
There is absolutely no need for eval.
The string interpolation construct ("Equals four: #{2+2}") is something that is handled by the coffeescript compiler, and will therefore not work inside an eval. But assuming the naming of the stuff inside the string does not change, you could easily rewrite it, so that eval("obj['#{field[1]}']") becomes eval("obj['"+field[1]+"']"). Assuming I got your question right of course.