Question

我有一个包含若干领域的数据框架。其中一个领域是“萨摩亚”,由于各种投入,我的样本用各种格式命名。以下是一些例子:

 "12" "250" "1248" "1_100111" "16_100111" "125_081811" "1249_100111"

The above examples represent the majority of the samples. I would like to change all of the samples to a 4 digit format so they can be easily sorted. The final result of the above examples would be:

 "0012" "0250" "1248" "0001" "0016" "0125" "1249"

Thus, in some cases zeros must be added and in other cases, the date marker must be cut off. It is very important that the changes are made within the context of a data frame and returned in the same format.

Answer 1

各位:

x <- c("12", "250", "1248", "1_100111", "16_100111", "125_081811", "1249_100111")
sprintf(as.numeric(gsub("(\d*)_*\d*$", "\1", x)), fmt="%04d")

[1] "0012" "0250" "1248" "0001" "0016" "0125" "1249"

Answer 2

sprintf("%04s",
  sub("_.+", "", c("12", "250", "1248", "1_100111", "16_100111", 
                   "125_081811", "1249_100111" ) )
[1] "0012" "0250" "1248" "0001" "0016" "0125" "1249"

友情链接