Each identifier is a nonempty sequence of letters, digits, and underscores that must not begin with a digit.

每个标识符都是字母、数字和下划线的非空序列，且序列不能以数字开头。

youdao

Each identifier is a nonempty sequence of letters, digits, and underscores that must not begin with a digit.

每个标识符都是字母、数字和下划线的非空序列，且序列不能以数字开头。

youdao