[英]In R, how can I manipulate variable in dataframe using regular expression?
This is the dataset 这是数据集
df1 <- data.frame("id" = c("ebi.ac.uk:MIAMExpress:Reporter:A-MEXP-503.100044",
"ebi.ac.uk:MIAMExpress:Reporter:A-MEXP-783.100435",
"ebi.ac.uk:MIAMExpress:Reporter:C-DEA-783.100435"),
"Name" = c("ABC", "DEF", ""))
The product of the dataset 数据集的乘积
id Name
1 ebi.ac.uk:MIAMExpress:Reporter:A-MEXP-503.100044 ABC
2 ebi.ac.uk:MIAMExpress:Reporter:A-MEXP-503.100435 DEF
3 ebi.ac.uk:MIAMExpress:Reporter:A-MEXP-503.100488
I want to make the dataframe look like this 我想使数据框看起来像这样
id Name
1 100044 ABC
2 100435 DEF
3 100488 NA
Can anyone show me how to approach this problem? 谁能告诉我如何解决这个问题?
Regex way to find the last dot: 正则表达式查找最后一个点的方法:
df1$id <- as.character(df1$id)
regexpr("\\.[^\\.]*$", df1$id) # may not need \\ on second one
or sapply(gregexpr("\\\\.", x), tail, 1)
或sapply(gregexpr("\\\\.", x), tail, 1)
Easier to remember, non-regex way: 较容易记住的非正则表达式方式:
df1$id <- as.character(df1$id)
df1$id <- sapply(strsplit(df1$id,split="\\."),tail,1)
df1$Name[df1$Name == ""] <- NA
df1
id Name 1 100044 ABC 2 100435 DEF 3 100435 <NA>
sapply(strsplit(df1$id,split="\\\\."),tail,1)
is from here . sapply(strsplit(df1$id,split="\\\\."),tail,1)
从这里开始 。
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