commit 1a798cd58f6bf653c3ce56dd3c881cb92ecf4e5d
parent b19b7f6717c20743f01613ec932f27559b774e80
Author: David Eisinger <[email protected]>
Date: Sun, 16 Jul 2023 00:22:49 -0400
Go maps
Diffstat:
1 file changed, 10 insertions(+), 0 deletions(-)
diff --git a/content/notes/golang/index.md b/content/notes/golang/index.md
@@ -116,7 +116,17 @@ I find [Go][1] really compelling, even though it's not super applicable to my jo
> Usually, a struct is used to create a custom error type. By convention, custom error type names should end with `Error`. Also, it is best to set up the `Error() string` method with a pointer receiver, see this [Stackoverflow comment](https://stackoverflow.com/a/50333850) to learn about the reasoning. Note that this means you need to return a pointer to your custom error otherwise it will not count as `error` because the non-pointer value does not provide the `Error() string` method.
+* [Maps][20]
+
+> A Go map type looks like this: `map[KeyType]ValueType`
+
+> To initialize a map, use the built in `make` function: `m = make(map[string]int)`
+
+> This statement retrieves the value stored under the key `"route"` and assigns it to a new variable i: `i := m["route"]`. If the requested key doesn’t exist, we get the value type’s _zero value_. In this case the value type is `int`, so the zero value is `0`.
+
+> A two-value assignment tests for the existence of a key: `i, ok := m["route"]`
[17]: https://stackoverflow.com/a/40951013
[18]: https://go.dev/doc/effective_go#named-results
[19]: https://exercism.org/tracks/go/concepts/errors
+[20]: https://go.dev/blog/maps
