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rstandardized

scale variables in dataframe using another dataframe


I have a dataframe with following variables

dat <- data.frame(cell.ID = 1:10, cell.name = letters[1:10], 
              groupID = rep(1:2, each = 5), 
              x1 = rnorm(10), x2 = rnorm(10), 
              x3 = rnorm(10), x4= rnorm(10), 
              x5 = rnorm(10), x6 = rnorm(10))

I have a mean and sd stored to normalise x1 to x6 in another dataframe

norm_fin <- data.frame(variable = paste0('x',1:6), 
                   meanVar = rnorm(6),
                   SdVar = rnorm(6))

I want to create a new dataframe from dat after normalised x1 to x6. I did a loop solution

 varVec <- paste0('x',1:6)
 dat1 <- dat
 for(i in varVec){
  meanRef <- norm_fin$meanVar[norm_fin$variable == i]
  sdRef <- norm_fin$SdVar[norm_fin$variable == i]
  dat1[, i] <- (dat[, i] - meanRef)/sdRef
}

Is there another solution without using a loop?


Solution

  • We can convert the data into long format and then left join norm_find, calculate the value and then get the data back in wide format.

    library(dplyr)
    library(tidyr)
    
    dat %>%
      pivot_longer(cols = starts_with('x')) %>%
      left_join(norm_fin, by = c('name' = 'variable')) %>%
      mutate(val = (value - meanVar)/SdVar) %>%
      select(-value, -meanVar, -SdVar) %>%
      pivot_wider(names_from = name, values_from = val)
    
    # A tibble: 10 x 9
    #   cell.ID cell.name groupID     x1      x2     x3    x4     x5      x6
    #     <int> <fct>       <int>  <dbl>   <dbl>  <dbl> <dbl>  <dbl>   <dbl>
    # 1       1 a               1 -2.10   32.6   -0.797 0.705 -0.768  0.0217
    # 2       2 b               1 -1.36   16.3    0.125 0.353 -1.76   0.144 
    # 3       3 c               1  2.63   17.0   -0.751 0.933  0.394  0.150 
    # 4       4 d               1 -0.690  11.6   -0.429 0.925 -6.60  -0.461 
    # 5       5 e               1 -0.559  -1.01  -0.316 0.898 -4.64   0.229 
    # 6       6 f               2  2.98   43.2   -1.47  0.833  0.105 -0.525 
    # 7       7 g               2  0.181  18.9    1.27  0.767 -1.36   0.802 
    # 8       8 h               2 -3.67  -27.6    0.528 0.467 -1.23  -0.122 
    # 9       9 i               2 -2.38   22.7   -0.873 0.348 -3.77   0.0778
    #10      10 j               2 -1.84    0.557  1.72  0.311 -2.01   0.0379
    

    data

    set.seed(123)
    dat <- data.frame(cell.ID = 1:10, cell.name = letters[1:10], 
                      groupID = rep(1:2, each = 5), 
                      x1 = rnorm(10), x2 = rnorm(10), 
                      x3 = rnorm(10), x4= rnorm(10), 
                      x5 = rnorm(10), x6 = rnorm(10))
    
    norm_fin <- data.frame(variable = paste0('x',1:6), 
                           meanVar = rnorm(6),
                           SdVar = rnorm(6))