数据框列属性转换

##-Convert Data Frame Column to Numeric in R (2 Examples) | Change Factor, Character & Integer-##

#####Create Example Data

data <- data.frame(x1 = c(1, 5, 8, 2),      # Create example data frame

                  x2 = c(3, 2, 5, 2),

                  x3 = c(2, 7, 1, 2))

data$x1 <- as.factor(data$x1)                # First column is a factor

data$x2 <- as.character(data$x2)            # Second column is a character

data$x3 <- as.integer(data$x3)              # Third column is an integer

data                                        # Print data to RStudio console

sapply(data, class)                          # Get classes of all columns

####Example 1: Convert One Variable of Data Frame to Numeric

data$x1 <- as.numeric(as.character(data$x1))  # Convert one variable to numeric

sapply(data, class)                          # Get classes of all columns

####Example 2: Change Multiple Columns to Numeric

i <- c(1，2, 3)                                  # Specify columns you want to change

data[ , i] <- apply(data[ , i], 2,            # Specify own function within apply

                    function(x) as.numeric(as.character(x)))

sapply(data, class)                          # Get classes of all columns

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reference：https://statisticsglobe.com/convert-data-frame-column-to-numeric-in-r

Convert Data Frame Column to Numeric in R (2 Example Codes)