R：删除每列中的NULL，同时保持列中的顺序

xjreopfe 于 2023-01-28 发布在其他

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我有一个R中包含NULL或编号的 Dataframe ：示例：

people1 <- c("Variety 1", "Variety 2", "Variety 3", "Variety 4", "Variety 5")
people2 <- c("Variety 4", "Variety 3", "Variety 2", "Variety 1", "NULL")
people3 <- c("Variety 3", "Variety 2", "NULL", "Variety 4", "Variety 1")
df2 <- data.frame(people1, people2, people3)

对于每一列，如果有NULL或NA，我希望将它们删除，并将下一项上移以进行替换，这样列可以以NULL结尾，但不会在中间。
你能帮忙吗？谢谢!

来源：https://stackoverflow.com/questions/75258663/r-remove-null-in-each-column-while-keeping-order-in-the-column

2条答案

按热度按时间

mnowg1ta1#

请注意，在我回答问题后，该问题发生了变化，原始问题的答案位于底部的"旧问题"下。新问题的答案为：

replace(df2, TRUE, lapply(df2, function(x) c(x[x != "NULL"], x[x == "NULL"])))

给出：

people1   people2   people3
1 Variety 1 Variety 4 Variety 3
2 Variety 2 Variety 3 Variety 2
3 Variety 3 Variety 2 Variety 4
4 Variety 4 Variety 1 Variety 1
5 Variety 5      NULL      NULL

旧的

将"NULL"值转换为NA，并使用na.locf（最后一次出现的值结转）。如果有多个连续的"NULL"值，也可以使用此方法。

library(zoo)

m <- as.matrix(df2)
replace(df2, TRUE, na.locf(ifelse(m == "NULL", NA, m)))

给出：

people1   people2   people3
1 Variety 1 Variety 4 Variety 3
2 Variety 2 Variety 3 Variety 2
3 Variety 3 Variety 2 Variety 2
4 Variety 4 Variety 1 Variety 4
5 Variety 5 Variety 1 Variety 1

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mepcadol2#

df3 <- data.frame(
  people1 = c(people1[people1 != "NULL"], people1[people1=="NULL"]),
  people2 = c(people2[people2 != "NULL"], people2[people2=="NULL"]),
  people3 = c(people3[people3 != "NULL"], people3[people3=="NULL"])
        )

将适用于“NULL”字符串。

> df3
    people1   people2   people3
1 Variety 1 Variety 4 Variety 3
2 Variety 2 Variety 3 Variety 2
3 Variety 3 Variety 2 Variety 4
4 Variety 4 Variety 1 Variety 1
5 Variety 5      NULL      NULL

赞(0）回复(0）举报 2023-01-28

我来回答

R：删除每列中的NULL，同时保持列中的顺序

2条答案

旧的

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