First, the definition
1. Mapping: key (index, can be understood as the attribute) and the value (data) corresponding to
2. Usage:
two. Functions and methods:
Third, the application scenarios
1. Mapping of expression
2. traversal
First, the definition
1. Mapping: key (index, can be understood as the attribute) and the value (data) corresponding to
2. Usage:
two. Functions and methods:
Third, the application scenarios
1. Mapping of expression
2. traversal