识别R

Question

我有一个从运行grep()创建的矢量命名列表。我想找到那些没有找到任何价值的元素，或者找到了一堆NA的元素。我该怎么做？

我试过了，但没有走得太远。

MyList<-c("Hello World", "a123 234","Hi world","a12345678 09876","publ school")
look_New<-c("world","a123","a1234","121314","pub school",NA) #this was generated using different code.
look_Old<-c("a","b","c","d","e","f") #this was generated using different code.
Look<-data.frame(look_New,look_Old,stringsAsFactors=FALSE)

Result<-lapply(Look$look_New, grep, x = MyList,ignore.case=TRUE)
names(Result)<-Look$look_Old

#which elements are null?
Look$look_Old[which(sapply(Result,length)==0)]

2个问题：

问题：1）

问题是上面的代码没有告诉我f有一堆NA s。但是，它确实显示了d和e

预期输出为：

d
e
f

问题2：

无论如何我可以用零向量替换这么多的NA吗？即如果我运行Results$f，它应显示在下方（正如我通过运行Results$e得到的那样：

Result$f
integer(0)

非常感谢任何帮助。

Answer 1

我们可以尝试

v1 <- sapply(Result, function(x) length(x)==0 | all (is.na(x)))
names(v1)[v1]
#[1] "d" "e" "f"

或使用Filter

names(Filter(function(x) !length(x)|all(is.na(x)), Result))

Answer 2

删除lengths()值后使用NA：

names(Result)[!lengths(lapply(Result, na.omit))]
#[1] "d" "e" "f"