r - 用新值填充数据框行

Question

我想用预先存在的数据(根据一列的名称)拟合一个空数据框。假设我的空数据是:

        #define empty data.frame
        predictor.names <- c("LO3","Tx","Gh","RH","SR","ST","TC","U10","WF","SF","F","VW","VS","V","D","day")
        dat <- data.frame("pred"=predictor.names,"MAM"=0)
        rownames(dat) <- predictor.names

现在，我想用以下值填充行:

          x  Freq
         SR   392
         RH   350
         day  253
          Tx   90
         LO3   28
          ST    7
          TC    5
          WF    5
          VS    2
          SF    1

然后，我试过:

       dat[which(dat$pred%in%temp[[1]]),2] <- temp[[2]]

但它不起作用，因为变量的顺序不同..
它将 392 添加到第一个 LO3，依此类推。
所以我想用循环来做到这一点..但必须有另一种更简单的方法..
任何想法/建议？

提前致谢!

Answer 1

你可以试试 match获取数字索引并将其用于分配值。

 indx <- match(temp$x, dat$pred)
 dat$MAM[indx] <- temp$Freq

数据

 temp <- structure(list(x = c("SR", "RH", "day", "Tx", "LO3", "ST", 
 "TC", 
 "WF", "VS", "SF"), Freq = c(392L, 350L, 253L, 90L, 28L, 7L, 5L, 
 5L, 2L, 1L)), .Names = c("x", "Freq"), class = "data.frame",
 row.names = c(NA, -10L))