R gsub数和变量空间

Question

With gsub I am able to remove the # from these person variables, however the way I am trying to remove the random number is not correct. I also would like to remove the space after the persons name as well but keep the space in the middle of the name.

c('mike smith #99','John johnson #2','jeff johnson #50') -> person

c(1:99) -> numbers

person <- gsub("#", "", person, fixed=TRUE)

# MY ISSUE
person <- gsub(numbers, "", person, fixed=TRUE)

df <- data.frame(PERSON = person)

Current Results:

PERSON
mike smith 99
John johnson 2
jeff johnson 50

Expected Results:

PERSON
mike smith
John johnson
jeff johnson

Answer 1

Here's another pattern as an alternative:

> gsub("(\\.*)\\s+#.*", "\\1", person)
[1] "mike smith"   "John johnson" "jeff johnson"

In the above regex, (\\\\.*) will match a subgroup of any characters before a space ( \\\\s+ ) following by # symbol and following by anything. Then \\\\1 indicates that gsub should replace all the original string with that subgroup (\\\\.*)

An easier way to get your desired output is :

> gsub("\\s+#.*$", "", person)
[1] "mike smith"   "John johnson" "jeff johnson"

The above regex \\\\s+#.*$ indicates that everything consisting of space ( \\\\s+ ), a # symbol and everyting else until the end of string ( \\.$ ) should be removed.

Using str_extract_all from stringr package

> library(stringr)
> str_extract_all(person, "[[a-z]]+", simplify = TRUE)
     [,1]   [,2]     
[1,] "mike" "smith"  
[2,] "ohn"  "johnson"
[3,] "jeff" "johnson"

Also you can use:

library(stringi)
stri_extract_all(person, regex="[[a-z]]+", simplify=TRUE)

Answer 2

c('mike smith #99','John johnson #2','jeff johnson #50') -> person
sub("\\s+#.*", "", person)
[1] "mike smith"   "John johnson" "jeff johnson"

Answer 3

We can create the pattern with paste

pat <- paste0("\\s*#(", paste(numbers, collapse = "|"), ")")
gsub(pat, "", person)
#[1] "mike smith"   "John johnson" "jeff johnson"

---

Note that the above solution was based on creating pattern with 'numbers'. If it is only to remove the numbers after the # including it

sub("\\s*#\\d+$", "", person)
#[1] "mike smith"   "John johnson" "jeff johnson"

---

Or another option is

unlist(strsplit(person, "\\s*#\\d+"))

NOTE: All the above are base R methods

---

library(tidyverse)
data_frame(person) %>% 
      separate(person, into = c("person", "notneeded"), "\\s+#") %>% 
      select(person)

Answer 4

This could alternately be done with read.table .

read.table(text = person, sep = "#", strip.white = TRUE, 
  as.is = TRUE, col.names = "PERSON")

giving:

        PERSON
1   mike smith
2 John johnson
3 jeff johnson

Answer 5

An alternative that deletes any sequence of non (lowercase) alphabetic characters at the end of the string.

gsub("[^a-z]+$", "", person)
[1] "mike smith"   "John johnson" "jeff johnson"

If you want to allow for words that are all upper case or end with an uppercase character.

gsub("[^a-zA-Z]+$", "", person)

Some names might end with . :

gsub("[^a-zA-Z.]+$", "", person)