如何用 R 中的字符串替换 NA？

在本文中，我们将讨论如何在 R 编程语言中用字符串替换 NA。 NA 代表 Not a Number，我们可以将 NA 替换为数据框中的字符串。

为演示创建数据框：

R

# 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         
2 ojaswi     java     hyd
3         jsp  tenali
4 ramesh       guntur

示例 1：将 NA 替换为一列中的字符串

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

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

where

1. dataframe  is the input dataframe
2. column_name is the column replace with the string

R程序用给定列中的字符串替换NA

R

# 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
data$subjects = data$subjects %>% replace_na('python')
  
# replace NA with sri devi in name column
data$name = data$name %>% replace_na('sri devi')
  
print(data)

输出：

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


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

示例 2：用多列中的字符串替换 NA

这里我们使用与上面相同的方法，但是，要替换多个列，我们必须在列表函数中指定多个列

Syntax: dataframe %>% replace_na(list(column1 = ‘string’, column2 = ‘string’,.,columnn = ‘string’,))

R

# 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         
2 ojaswi     java     hyd
3         jsp  tenali
4 ramesh       guntur


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