want to remove certain value from the vector in R

Question

I have vector in the below form:

a<-

[1] "[1]"                "\"0\""              "\"0\""              "\"0\""              "\"0\""              "[5]"                "\"0\""              "\"0\""              "\"0\""              "\"0\""             
[11] "[9]"                "\"0\""              "\"0\""              "\"0\""              "\"0\""              "[13]"               "\"0\""              "\"0\""              "\"0\""              "\"0\"" 

I want to remove all the numbers "[1]","[5]","[11]","[15]"...."[1500]" so on using gsub or regex in R. I have given a try below:

remove<- gsub("[0:9]", a)

But getting following error:

Error in gsub("[0:9]", a) : argument "x" is missing, with no default

Thanks in advance!

Answer 1

Note that gsub only removes text inside character vector items, it does not remove the items themselves. In this case, you need a grep -like solution.

You may use a simple pattern to identify those items:

^\[\d+]$

See the regex demo .

Details

• ^ - start of string
• \\[ - a [ char
• \\d+ - 1+ digits
• ] - a literal ]
• $ - end of string.

Then, use it with grep command with invert=TRUE option to only keep the items that do not match this regex, and value=TRUE to get the values rather than indices.

See the R demo :

> a <- c("[1]", "\"0\"")
> grep("^\\[\\d+]$", a, invert=TRUE, value=TRUE)
[1] "\"0\""