Multiple readers, no writers is okay: https://groups.google.com/d/msg/golang-nuts/HpLWnGTp-n8/hyUYmnWJqiQJ One writer, no readers is okay. (Maps wouldn’t be much good otherwise.) Otherwise, if there is at least one writer and at least one more either writer or reader, then all readers and writers must use synchronization to access the map. A mutex works fine for this.
You have two choices: The first and most performant is to use associateBy function that takes two lambdas for generating the key and value, and inlines the creation of the map: val map = friends.associateBy({it.facebookId}, {it.points}) The second, less performant, is to use the standard map function to create a list of Pair which can … Read more
In Go there are no reference types like you have them in C++. In Go everything is passed by value. When the term “reference type” is used in Go, it means a type that references to the data they ought to represent (via pointers). Slices are small, struct-like data structures represented by the type reflect.SliceHeader: … Read more
Dictionaries in Swift (and other languages) are not ordered. When you iterate through the dictionary, there’s no guarantee that the order will match the initialization order. In this example, Swift processes the “Square” key before the others. You can see this by adding a print statement to the loop. 25 is the 5th element of … Read more
I like your reduce version just fine. I think it’s idiomatic. Here’s a version using list comprehension anyways. (defn foo [m f] (into {} (for [[k v] m] [k (f v)])))
You can’t change values associated with keys in a map, you can only reassign values. This leaves you 2 possibilities: Store pointers in the map, so you can modify the pointed object (which is not inside the map data structure). Store struct values, but when you modify it, you need to reassign it to the … Read more
When working with dictionaries you have to remember that a key might not exist in the dictionary. For this reason, dictionaries always return optionals. So each time you access the dictionary by key you have to unwrap at each level as follows: bugsDict[“ladybug”]![“spotted”]![“red”]!++ I presume you know about optionals, but just to be clear, use … Read more
Using additionalPropertiesis the proper way to describe hashmap with OpenAPI (fka. Swagger) Specification but Swagger UI do not render them for now. The issue is tracked here https://github.com/swagger-api/swagger-ui/issues/1248 Meanwhile you can use this trick: define a non required property (defaultin the example below) of the same type of the map’s objects and give some hint … Read more
Yes it’s possible. In OpenAPI (fka. Swagger) 2.0 and 3.0, a hashmap is always a <string, something> map: The key is always a string and do not need to be defined. The value type is what you want and is defined with additionalProperties. Let’s say you want to describe a <string, string> hashmap like this … Read more