In IntelliJ IDEA: In File Menu → Project Structure → Project, change Project Language Level to 8.0 – Lambdas, type annotations etc. For Android 3.0+ Go File → Project Structure → Module → app and In Properties Tab set Source Compatibility and Target Compatibility to 1.8 (Java 8) Screenshot:
A final variable means that it can be instantiated only one time. in Java you can’t reassign non-final local variables in lambda as well as in anonymous inner classes. You can refactor your code with the old for-each loop: Even if I don’t get the sense of some pieces of this code: you call a … Read more
Got it. I assumed it’d figure out that the > operator returned a bool (per documentation). But apparently it is not so.
Look at the following: Is this a lambda returning (y, [1,2,3]) (thus map only gets one parameter, resulting in an error)? Or does it return y? Or is it a syntax error, because the comma on the new line is misplaced? How would Python know what you want? Within the parens, indentation doesn’t matter to python, so you … Read more
A lambda is an anonymous function: It is often used in functions such as sorted() that take a callable as a parameter (often the key keyword parameter). You could provide an existing function instead of a lambda there too, as long as it is a callable object. Take the sorted() function as an example. It’ll return the given iterable in sorted order: but that sorts uppercased … Read more
You can just copy the value of readln2 into a final variable: If you want to grab a new random line each time, you can either cache the lines of interest and select a random one in the event handler: Or you could just re-read the file in the event handler. The first technique is (much) faster but could … Read more
The problem arises because your lambda expression does not reference this or a member of this but a member of the outer this. Had you written class B like the compiler rejected it without any doubts as accessing innerData implies accessing this. The point about the outer instance is that it is a constant which is even available when the inner instance has not been fully … Read more
You just need to use apply on the groupby object. I modified your example data to make this a little more clear: Which prints:
The syntax you’re looking for: But you can’t use print or raise in a lambda.
A lambda is an anonymous function: It is often used in functions such as sorted() that take a callable as a parameter (often the key keyword parameter). You could provide an existing function instead of a lambda there too, as long as it is a callable object. Take the sorted() function as an example. It’ll return the given iterable in sorted order: but that sorts uppercased … Read more