How to view the number of rows and columns in R language?

In R, you can use the functions nrow() and ncol() to respectively check the number of rows and columns in a data frame or matrix.

For example, suppose there is a data frame df, we can view the number of rows and columns using the following method:

# 查看行数
nrow(df)

# 查看列数
ncol(df)

To check the number of rows and columns of a matrix mat, you can also use the functions nrow() and ncol().

# 查看行数
nrow(mat)

# 查看列数
ncol(mat)

Please note that these functions only work with data frames and matrices, and will return an error for other types of objects such as vectors or lists.