Is it possible to capture by const reference in a lambda expression? I want the assignment marked below to fail, for example: #include <algorithm> #include <string> using namespace std; int main() { string strings[] = { “hello”, “world” }; static const size_t num_strings = sizeof(strings)/sizeof(strings[0]); string best_string = “foo”; for_each( &strings[0], &strings[num_strings], [&best_string](const string& s) … Read more
When I iterate over a collection using the new syntactic sugar of Java 8, such as myStream.forEach(item -> { // do something useful }); Isn’t this equivalent to the ‘old syntax’ snippet below? myStream.forEach(new Consumer<Item>() { @Override public void accept(Item item) { // do something useful } }); Does this mean a new anonymous Consumer … Read more
Kotlin has very nice iterating functions, like forEach or repeat, but I am not able to make the break and continue operators work with them (both local and non-local): repeat(5) { break } (1..5).forEach { continue@forEach } The goal is to mimic usual loops with the functional syntax as close as it might be. It … Read more
I am playing around with lazy functional operations in Java SE 8, and I want to map an index i to a pair / tuple (i, value[i]), then filter based on the second value[i] element, and finally output just the indices. Must I still suffer this: What is the equivalent of the C++ Pair<L,R> in … Read more
I am looking at the new implementations in C# 7.0 and I find it interesting that they have implemented local functions but I cannot imagine a scenario where a local function would be preferred over a lambda expression, and what is the difference between the two. I do understand that lambdas are anonymous functions meanwhile … Read more
I have this query: int maxShoeSize = Workers .Where(x => x.CompanyId == 8) .Max(x => x.ShoeSize); What will be in maxShoeSize if company 8 has no workers at all? UPDATE: How can I change the query in order to get 0 and not an exception? 11 Answers 11
I have a list of objects say car. I want to filter this list based on some parameter using Java 8. But if the parameter is null, it throws NullPointerException. How to filter out null values? Current code is as follows requiredCars = cars.stream().filter(c -> c.getName().startsWith(“M”)); This throws NullPointerException if getName() returns null. 6 Answers … Read more
Is it possible to have a PHP function that is both recursive and anonymous? This is my attempt to get it to work, but it doesn’t pass in the function name. $factorial = function( $n ) use ( $factorial ) { if( $n <= 1 ) return 1; return $factorial( $n – 1 ) * … Read more
I was testing out some new features of Java 8 and copied the example into my IDE (Eclipse originally, then IntelliJ) as shown here Eclipse offered no support whatsoever for lambda expressions, and IntelliJ kept reporting an error Lambda expressions not supported at this language level I would like to know if this is a … Read more
I’m using java lambda to sort a list. how can I sort it in a reverse way? I saw this post, but I want to use java 8 lambda. Here is my code (I used * -1) as a hack Arrays.asList(files).stream() .filter(file -> isNameLikeBaseLine(file, baseLineFile.getName())) .sorted(new Comparator<File>() { public int compare(File o1, File o2) { … Read more
