我的資料框中有一列混合了一些日期和字串值。我想專門選擇日期并轉換為 UNIX 時間戳并保留字串值。如何做到這一點？
樣本資料
|column1|
---------
|2020-12-21 00:00:00|
|test1|
|test2|
|test3|
|2021-12-21 00:00:00|
預期結果
|Column1|
---------------
|1608508800|
|test1|
|test2|
|test3|
|1608508800|
uj5u.com熱心網友回復：
x = read.table(text = 'column1
2020-12-21 00:00:00
test1
test2
test3
2021-12-21 00:00:00', sep = ";", header = T)
uts = as.numeric(as.POSIXct(x$column1, format = "%Y-%m-%d %H:%M:%S", tz = "UTC"))
uts_i = which(!is.na(uts))
x$column1[uts_i] = uts[uts_i]
x
# column1
# 1 1608508800
# 2 test1
# 3 test2
# 4 test3
# 5 1640044800
或與dplyr：
x %>%
mutate(
uts = as.numeric(as.POSIXct(x$column1, format = "%Y-%m-%d %H:%M:%S", tz = "UTC")),
column1 = coalesce(as.character(uts), column1)
) %>%
select(-uts)
# column1
# 1 1608508800
# 2 test1
# 3 test2
# 4 test3
# 5 1640044800
轉載請註明出處，本文鏈接：https://www.uj5u.com/qukuanlian/470806.html