r - "NA"字符串转换为

Question

我有一个 csv包含国家名称及其 ISO 代码的文件。这是它的样子:

"Name","Code"
"Afghanistan","AF"
"Albania","AL"
"Algeria","DZ"
"Namibia","NA"

我在 data.frame 中阅读了它使用以下代码:

cc = read.csv("countries.csv", header=TRUE, stringsAsFactors=FALSE, 
                                           colClasses = c("character")) 

数据如下所示:

Name         Code
Afghanistan  AF
Albania      AL
Algeria      DZ
Namibia      <NA>

字符串 "NA"正在转换为 <NA>即使我明确设置 colClasses = c("character") .

我如何获得 "NA"显示为 "NA"在 data.frame ?

Answer 1

尝试设置 na.strings显式参数 - 默认为“NA”:

    cc = read.csv("countries.csv", header=TRUE, stringsAsFactors=FALSE,
                              colClasses = c("character"),  na.strings="" )