如何在数据帧中操作变量

Question

I need to do some manipulations in a factor inside my data frame with name phone number. the variables must be numeric with lenght 5 also not contains special char and I want to change the format AO-11111, VQ-11111from to 111111 it means erase the first chars and finally transform the rest of variables to na

My data.frame is derived from a .csv file.initial phone_number is a factor data such that phone_number VQ-40773 VQ-43685 VQ-44986 40270 41694 42623 . .

Answer 1

strsplit function will help you to get the value out string.

 str="VQ-40773"
(strsplit(str,"-"))[[1]][2] //will return 40773

Answer 2

If you want to remove anything the precedes a dash, then:

 sub("^([^-]+[-])(.+)", "\\2", phone_number)

> phone_number <- scan(what="")
1:     VQ-40773
2:     VQ-43685
3:     VQ-44986
4:     40270
5:     41694
6:     42623
7: 
Read 6 items
> sub("^([^-]+[-])(.+)", "\\2", phone_number)
[1] "40773" "43685" "44986" "40270" "41694" "42623"
> as.numeric(sub("^([^-]+[-])(.+)", "\\2", phone_number))
[1] 40773 43685 44986 40270 41694 42623

The nchar function would allow checking the lengths of a character vector. Post an adequate example and, please, do make a greater effort to get punctuation and capitalization correct.