R语言 如何用字符串替换NA

在这篇文章中，我们将讨论如何在R编程语言中用字符串替换NA。NA代表不是一个数字，我们可以在数据框架中用字符串替换NA。

创建Demonestration的数据框架

# create a dataframe
data = data.frame(name = c("sravan","ojaswi",NA,"ramesh"),
                  subjects = c(NA,"java","jsp",NA),
                  address = c(NA,"hyd","tenali","guntur"))
  
# display
data

输出

    name subjects address
1 sravan     <NA>    <NA>
2 ojaswi     java     hyd
3   <NA>      jsp  tenali
4 ramesh     <NA>  guntur

例1:在一列中用字符串替换NA

我们可以使用replace_na()函数将特定列中的NA替换为字符串，我们必须导入tidyr包。

语法: dataframe$column_name%>% replace_na(‘string’)

其中

1. dataframe是输入的数据框架
2. column_name是用字符串替换的列

R程序将给定列中的NA替换为字符串

# load the library
library("tidyr")
  
# create a dataframe
data = data.frame(name = c("sravan","ojaswi",NA,"ramesh"),
                  subjects = c(NA,"java","jsp",NA),
                  address = c(NA,"hyd","tenali","guntur"))
  
# display
print(data)
  
# replace NA with python in subjects column
datasubjects = datasubjects %>% replace_na('python')
  
# replace NA with sri devi in name column
dataname = dataname %>% replace_na('sri devi')
  
print(data)

输出

   name subjects address
1 sravan     <NA>    <NA>
2 ojaswi     java     hyd
3   <NA>      jsp  tenali
4 ramesh     <NA>  guntur


   name subjects address
1 sravan     <NA>    <NA>
2 ojaswi     java     hyd
3   <NA>      jsp  tenali
4 ramesh     <NA>  guntur

例2:在多列中用字符串替换NA值

这里我们使用与上面相同的方法，但是，要在多列中替换，我们必须在一个列表函数中指定多列

语法: dataframe %>% replace_na(list(column1 = 'string', column2 = 'string',.,columnn = 'string',))

# load the library
library("tidyr")
  
# create a dataframe
data = data.frame(name = c("sravan","ojaswi",NA,"ramesh"),
                  subjects = c(NA,"java","jsp",NA),
                  address = c(NA,"hyd","tenali","guntur"))
  
# display
print(data)
  
  
# replace NA with python in subjects
# column and sri devi in name column
data = data %>% replace_na(list(subjects='python', name='sri devi'))
  
print(data)

输出

   name subjects address
1 sravan     <NA>    <NA>
2 ojaswi     java     hyd
3   <NA>      jsp  tenali
4 ramesh     <NA>  guntur


   name subjects address
1 sravan     <NA>    <NA>
2 ojaswi     java     hyd
3   <NA>      jsp  tenali
4 ramesh     <NA>  guntur