从 R 中的数据中删除非数字值

Removing non-numeric values from data in R

我有大量数据要导入。令人恼火的是,所有 "NA" 值都显示为“*****”,当我将数据读入 R 时,它会导入为因子矩阵。

str(x)
'data.frame':   5 obs. of  5 variables:
 $ 1: Factor w/ 704 levels "*****","0","100.1",..: 2 457 531 550 598
 $ 2: Factor w/ 689 levels "*****","0","100",..: 473 2 113 440 515
 $ 3: Factor w/ 711 levels "*****","0","100.1",..: 485 379 2 184 514
 $ 4: Factor w/ 709 levels "*****","0","100.1",..: 534 491 47 2 542
 $ 5: Factor w/ 681 levels "*****","0","100.6",..: 590 561 548 554 2


> x[988:993,988:993]
      988   989   990   991   992   993
988     0 ***** ***** ***** ***** *****
989 *****     0 ***** ***** ***** *****
990 ***** *****     0 ***** ***** *****
991 ***** ***** *****     0 ***** *****
992 ***** ***** ***** *****     0 *****
993 ***** ***** ***** ***** *****     0

矩阵的最后几个值没有数据,显示为“*****”。我需要一种将它们的值设置为“0”的方法,以便我的矩阵读取为数字。

读取文件时添加两个参数:

na.strings = "*****", stringsAsFactors = FALSE