iter2

Go iter utilities.

1. Operations of iterator:

   Zipping two Seqs to one Seq of pairs:

   func ExampleZip() {
       ks := []int{1, 2, 3}
       vs := []string{"one", "two", "three"}
   
       type pair struct {
           N   int
           Str string
       }
   
       s := slices.Collect(iter2.Zip(slices.Values(ks), slices.Values(vs), func(i int, s string) pair { return pair{i, s} }))
       fmt.Println(s)
       // Output: [{1 one} {2 two} {3 three}]
   }

   Zipping tow Seqs to one Seq2:

   func ExampleZip2() {
       ks := []int{1, 2, 3}
       vs := []string{"one", "two", "three"}
       zipped := iter2.Zip2(slices.Values(ks), slices.Values(vs))
       m := maps.Collect(zipped)
       for k, v := range m {
           fmt.Println(k, v)
       }
       // Unordered output:
       // 1 one
       // 2 two
       // 3 three
   }

   Concating 2 Seqs:

   func ExampleConcat() {
       seq1 := slices.Values([]int{1, 2, 3})
       seq2 := slices.Values([]int{4, 5})
       seq := iter2.Concat(seq1, seq2)
       fmt.Println(slices.Collect(seq))
       // Output:
       // [1 2 3 4 5]
   }

2. Map DB rows:

   import (
       "database/sql"
       _ "modernc.org/sqlite"
       // and more
   )
   
   func ExampleAllRows_tableStruct() {
       db, err := sql.Open("sqlite", ":memory:")
       if err != nil {
           panic(err)
       }
       q := `
   create temp table users (id integer, name text); -- Create temp table for queries.
   insert into users values (1, "User1"); -- Populate temp table.
   insert into users values (2, "User2");
   insert into users values (3, "User3");
   
   -- First result set.
   select * from users;
   `
       type User struct {
           ID   int
           Name string
       }
   
       users := slices.Collect(
           iter2.Map(
               iter2.MustAllRows(db.Query(q)), func(row iter2.Row) (user User) {
                   row.Scan(&user.ID, &user.Name)
                   return
               }))
       fmt.Println(users)
       // Should output:
       // [{1 User1} {2 User2} {3 User3}]
   }

More examples here.