将不等数组的列转换为 R 中的单个值列 [英] Transforming columns of unequal arrays to column of single values in R

问题描述

作为此之后的下一步 previous question，假设有多个长度不同的数组列.例如:

As a next step after this previous question, assume that there are multiple columns of arrays that do not have the same length. For example:

<头>

Col_A	Col_B	Col_C
[0.1,0.5,0.7]	[1.54E12, 1.54E12, 1.54E12]	[1, 3, 4, 5}

我如何采用这种格式并将其重新格式化为以下格式，在适当的情况下为 Col_A 和 Col_b 提供 NA:

How can I take this format and reformat it to the following giving NAs to Col_A and Col_b where appropriate:

<头>

Col_A	Col_B	Col_C
0.1	1.54E12	1
0.5	1.54E12	3
0.7	1.54E12	4
不适用	不适用	5

此代码适用于所有数组相等的情况，但如果数组不相等则会抛出错误:

This code works for when all arrays are equal but will throw an error if the arrays are not equal:

library(dplyr)
library(stringr)
library(tidyr)
df  %>% 
   mutate(across(everything(), str_extract_all, "(?<=\\[)[^]]+")) %>% 
   unnest(c(NDVIs, dates)) %>% 
   separate_rows(c(NDVIs, dates), sep=",\\s+", convert = TRUE)

推荐答案

我们可以使用 splitstackshape

library(splitstackshape)
library(data.table)
cSplit(setDT(df)[, lapply(.SD, gsub, pattern = "[][}]", 
    replacement = "")], names(df), sep=",", fixed = FALSE, "long")
#   Col_A    Col_B Col_C
#1:   0.1 1.54e+12     1
#2:   0.5 1.54e+12     3
#3:   0.7 1.54e+12     4
#4:    NA       NA     5

数据

df <- structure(list(Col_A = "[0.1,0.5,0.7]", Col_B = "[1.54E12, 1.54E12, 1.54E12]", 
    Col_C = "[1, 3, 4, 5}"), class = "data.frame", row.names = c(NA, 
-1L))

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