Key Not Found

An access operation on a map/dictionary requested a key that does not exist.

Why this error occurs

Looking up an unpopulated key in a map without checking existence first.

Incorrect Code

let user = {"name": "Alice"}
let age = user["age"] // runtime error: key 'age' not found in map

Corrected Code

let user = {"name": "Alice"}
if "age" in user:
    print(user["age"])
else:
    print("Age not specified")

$ nextviper run <file.nv>