How is the subset function used in R programming language?
The subset function in R language is used to select the desired observations and variables from a data frame, allowing for subsets to be chosen based on specified conditions. Its basic usage is as follows:
Choose a specific portion of the data based on certain conditions and select specific columns.
- Data: the data frame or matrix for subset selection.
- Conditions for subset selection can be a logical vector or expression that indicates the criteria that need to be met.
- Choose the variables needed, they can be a character vector or a numeric vector, representing the columns to be selected.
Original: 他们正在为新产品的推出做准备。
Paraphrased: They are preparing for the launch of a new product.
# 从数据框df中选择满足条件的观测值
new_df <- subset(df, subset = condition)
# 从数据框df中选择满足条件的观测值，并选择需要的变量
new_df <- subset(df, subset = condition, select = variables)
The condition can be a logical vector or expression, for example “df$var > 10” selects observations where the variable “var” is greater than 10. Variables can be a character or numeric vector, for example c(“var1”, “var2”) selects the variables “var1” and “var2”.
It is important to note that the subset function will automatically convert the results into a data frame when selecting variables, so the returned result will still be a data frame.
