如何在R中的值为NA时跳过paste()参数

Question

我有一个包含城市,州和国家列的数据框.我想创建一个串联的字符串:"城市,州,国家".但是,我的一个城市没有州(有一个国家NA).我希望那个城市的字符串是"城市,乡村".以下是创建错误字符串的代码:

# define City, State, Country
  city <- c("Austin", "Knoxville", "Salk Lake City", "Prague")
  state <- c("Texas", "Tennessee", "Utah", NA)
  country <- c("United States", "United States", "United States", "Czech Rep")
# create data frame
  dff <- data.frame(city, state, country)
# create full string
  dff["string"] <- paste(city, state, country, sep=", ")

当我显示时dff$string,我得到以下内容.请注意,最后一个字符串有一个NA,,不需要:

> dff["string"]
                               string
1        Austin, Texas, United States
2 Knoxville, Tennessee, United States
3 Salk Lake City, Utah, United States
4               Prague, NA, Czech Rep

我该怎么做才能跳过这一点NA,,包括sep = ", ".

Answer 1

另一种方法是事后修复它:

gsub("NA, ","",dff$string)

#[1] "Austin, Texas, United States"       
#[2] "Knoxville, Tennessee, United States"
#[3] "Salk Lake City, Utah, United States"
#[4] "Prague, Czech Rep"   

备选方案#2,一旦你有你的data.frame被叫,就要使用申请dff:

apply(dff, 1, function(x) paste(na.omit(x),collapse=", ") )

Answer 2

虽然迟到了，但unite提供了一种一步法：

dff %>% unite("string", c(city, state, country), sep=", ", remove = FALSE, na.rm = TRUE)

                              string           city     state       country
1        Austin, Texas, United States         Austin     Texas United States
2 Knoxville, Tennessee, United States      Knoxville Tennessee United States
3 Salk Lake City, Utah, United States Salk Lake City      Utah United States
4                   Prague, Czech Rep         Prague      <NA>     Czech Rep