r - NA 替换为空格

Question

我使用了相同的方法将 NA 替换为空格或其他字符，但由于某种原因，这个方法不起作用。我想将数据框中的 NA 替换为空白(年份和年度列)。我做错了什么？

shad.92 <- structure(list(year = c(1992, NA, NA, NA, NA), type = c("all age abundance index", 
"adjusted number of fish older than age 0 measured", "adjusted total number of fish measured", 
"percent YOY", "YOY abundance index"), September = c(755, 0, 
565, 100, 755), October = c(530, 0, 434, 100, 530), November = c(463, 
0, 338, 100, 463), December = c(266, 1, 136, 99.3, 264), Annual = c(2014, 
NA, NA, NA, 2012)), row.names = c(NA, -5L), class = c("tbl_df", 
"tbl", "data.frame"))

我尝试过，但没有成功:

shad.92 <- shad.92[is.na(shad.92)] <- ""

然后我尝试了从年份开始的一列:

shad.92$year <- as.character(shad.92$year)
    shad.92$year[is.na(shad.92$year)] <- " "
    shad.92 

但我得到的是引号而不是空格 ("")

Answer 1

我们可以将 mutate_at 与 replace_na 一起使用

library(dplyr)
library(tidyr)
shad.92 %>% 
       mutate_at(vars(year, Annual), replace_na, '')
# A tibble: 5 x 7
#  year   type                                              September October November December Annual
#  <chr>  <chr>                                                 <dbl>   <dbl>    <dbl>    <dbl> <chr> 
#1 "1992" all age abundance index                                 755     530      463    266   "2014"
#2 ""     adjusted number of fish older than age 0 measured         0       0        0      1   ""    
#3 ""     adjusted total number of fish measured                  565     434      338    136   ""    
#4 ""     percent YOY                                             100     100      100     99.3 ""    
#5 ""     YOY abundance index                                     755     530      463    264   "2012"