如何用R语言将字符(0)转换为NA? [英] How to convert character(0) to NA in a list with R language?

问题描述

如何在使用R语言的列表中将character(0)转换为NA?

How to convert character(0) to NA in a list with R language?

示例:

a = list("a", "character(0)", "b", "c")

到

a = list("a", "NA", "b", "c")

谢谢.

推荐答案

仅替换character(0)(假设您是指character(0)而不是"character(0)"):

Replace character(0) only (assume you meant character(0) instead of "character(0)"):

a = list("a", character(0), "b", "c")

lapply(a, function(x) if(identical(x, character(0))) NA_character_ else x)

#[[1]]
#[1] "a"

#[[2]]
#[1] NA

#[[3]]
#[1] "b"

#[[4]]
#[1] "c"

替换所有长度为0的元素:

Replace all length-0 elements:

a[lengths(a) == 0] <- NA_character_

a
#[[1]]
#[1] "a"

#[[2]]
#[1] NA

#[[3]]
#[1] "b"

#[[4]]
#[1] "c"

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