根据正则表达式匹配创建新列

问题

I would like to create a new column for relative standard deviation using following formula:stdev * 100 / abs(mean). I have over 40 variables, each with their own stdev and mean (so 80 columns). What I would like to do is use regular expressions to calculate the relative standard deviation from the 2 columns (stdev and mean) based on the preceding names. For example, for columns AceticAcid.stdevand AceticAcid.mean, calculate the relative standard deviation to automatically create a new column AcetiAcid.rsd. The equation being: AceticAcid.stdev * 100 / abs(AceticAcid.mean).

示例数据框

print(df)

  AceticAcid.mean AceticAcid.stdev Glucose.mean Glucose.stdev Propanol.mean Propanol.stdev
1        28.75775         0.911130     48.27333     4.4991249      144.4770       38.34122
2        78.83051        10.562110     28.13337     1.2304387      134.6402       31.76264
3        40.89769        17.848381     37.10283     0.2102977      132.0253       33.76568
4        88.30174        11.028700     32.90534     1.6396036      149.7135       21.56639
5        94.04673         9.132295     14.11699     4.7725182      132.7853       15.88455

所需的输出（不在乎新列的顺序）

print(df_rsd)

  AceticAcid.mean AceticAcid.stdev Glucose.mean Glucose.stdev Propanol.mean Propanol.stdev AceticAcid.rsd Glucose.rsd Propanol.rsd
1        28.75775         0.911130     48.27333     4.4991249      144.4770       38.34122       3.168294   9.3201039     26.53795
2        78.83051        10.562110     28.13337     1.2304387      134.6402       31.76264      13.398504   4.3735921     23.59076
3        40.89769        17.848381     37.10283     0.2102977      132.0253       33.76568      43.641536   0.5667969     25.57515
4        88.30174        11.028700     32.90534     1.6396036      149.7135       21.56639      12.489788   4.9827894     14.40511
5        94.04673         9.132295     14.11699     4.7725182      132.7853       15.88455       9.710380  33.8069175     11.96258

重复尝试... 我不想将这些写40次（必须有一种很好的正则表达式方式才能实现）：

df_rsd <- df %>% mutate(AceticAcid.rsd = AceticAcid.stdev * 100 / abs(AceticAcid.mean),
                        Glucose.rsd = Glucose.stdev * 100 / abs(Glucose.mean),
                        Propanol.rsd = Propanol.stdev * 100 / abs(Propanol.mean))

可复制的数据

structure(list(AceticAcid.mean = c(28.7577520124614, 78.8305135443807, 
40.89769218117, 88.3017404004931, 94.0467284293845), AceticAcid.stdev = c(0.911129987798631, 
10.5621097609401, 17.8483808878809, 11.0287002893165, 9.13229470606893
), Glucose.mean = c(48.2733338139951, 28.1333662476391, 37.1028254181147, 
32.9053360782564, 14.1169873066247), Glucose.stdev = c(4.49912485200912, 
1.2304386717733, 0.210297667654231, 1.63960359641351, 4.77251824573614
), Propanol.mean = c(144.476965803187, 134.64017030783, 132.025340688415, 
149.713488831185, 132.785289955791), Propanol.stdev = c(38.3412187267095, 
31.7626409884542, 33.7656808178872, 21.5663894917816, 15.884545892477
)), class = "data.frame", row.names = c(NA, -5L))