R Language View object type and length _r language view object type and length

A. View type

1. Guess Trial and error

Is.fun form, return True or False

You can also judge the second level

2. Direct view

Class View the first level category, mode view the second level category, TypeOf view the third level category

GL Function, GL (2,5) generates two factor levels, each factor level repeats 5 times the factor

Two. View length

1. Overview of objects

Str,attributes, universal view function for all objects

2. Specialized functions

Vectors, factors: length, other object types can also be viewed

Matrices, data boxes: Nrow rows, ncol columns

Arrays: Dim dimensions