I have a vector of names that looks like this:
names <- c("Verticordia (Cha)", "Whiteodendron\n(Loph)", "Platysace",
"Xanthostemon\n(Xan)", "Quercus (incl.\nCyclobalanopsis)\n(Fag)"
)
[1] "Verticordia (Cha)" "Whiteodendron\n(Loph)" "Platysace" "Xanthostemon\n(Xan)"
[5] "Quercus (incl.\nCyclobalanopsis)\n(Fag)"
I would like to conditionally remove all characters thatcome after a space or a \, including the space or the \. I have been able to remove the \ or the space using:
gsub("\n*","",names)
gsub(" *","",names)
However, I am having trouble getting the code to remove all following characters as well.
gsub("\n.*","",names)
gsub(" .*","",names)
You want the asterisk quantifier to apply to the dot (which is a wildcard matching all characters). Your version applied the quantifer to the newline or space character, so you were removing only strings of consecutive newlines or spaces.
Or all in 1 regex:
names.reduced <- gsub('[ \\\n].*', '', names)
[1] "Verticordia" "Whiteodendron" "Platysace" "Xanthostemon" "Quercus"
Related
There is ori_string ，how to using regexp to remove all the character not in chinese and english? Thanks!
ori_string<-"没a w t _ 中/国.sz"
the wished result is
"没awt中国sz"
I have coded it in python, as you didn't specify anything. The idea is here.
def remove_non_english_chinese(text):
# Use a regex pattern to match any character that is not a letter or number
pattern = r'[^a-zA-Z0-9\u4e00-\u9fff]'
# Replace all non-English and non-Chinese characters with an empty string
return re.sub(pattern, '', text)
Seems you want to remove punctuation and spaces:
> regex <- '[[:punct:][:space:]]+'
> gsub(regex, '', ori_string)
[1] "没awt中国sz"
I want to remove the comma and the apostrophe but the point of the following character. After that pass to numeric
I have this:
characterExample <- "234'564,900.99"
I want 234564900.99
I try the following but I can't:
result <- gsub("[:punct:].","", characterExample)
Another option is to explicitly remove the characters you want to remove:
gsub("[',]", "", characterExample)
#[1] "234564900.99"
``
An option is to not match the digits or the . by using ^ within the square bracket
gsub("[^0-9.]+","", characterExample)
#[1] "234564900.99"
Or another option is to make use of SKIP/FAIL for the ., while matching the rest of the punct
gsub("(\\.)(*SKIP)(*F)|[[:punct:]]+", "", characterExample, perl = TRUE)
#[1] "234564900.99"
NOTE: Both solutions make sure that it matches any punct characters other than the . and replace with blank ("")
It can also use the pipe symbol like this:
#Code
gsub(",|'","", characterExample)
Output:
gsub(",|'","", characterExample)
[1] "234564900.99"
I have the string in R
BLCU142-09|Apodemia_mejicanus
and I would like to get the result
Apodemia_mejicanus
Using the stringr R package, I have tried
str_replace_all("BLCU142-09|Apodemia_mejicanus", "[[A-Z0-9|-]]", "")
# [1] "podemia_mejicanus"
which is almost what I need, except that the A is missing.
You can use
sub(".*\\|", "", x)
This will remove all text up to and including the last pipe char. See the regex demo. Details:
.* - any zero or more chars as many as possible
\| - a | char (| is a special regex metacharacter that is an alternation operator, so it must be escaped, and since string literals in R can contain string escape sequences, the | is escaped with a double backslash).
See the R demo online:
x <- c("BLCU142-09|Apodemia_mejicanus", "a|b|c|BLCU142-09|Apodemia_mejicanus")
sub(".*\\|", "", x)
## => [1] "Apodemia_mejicanus" "Apodemia_mejicanus"
We can match one or more characters that are not a | ([^|]+) from the start (^) of the string followed by | in str_remove to remove that substring
library(stringr)
str_remove(str1, "^[^|]+\\|")
#[1] "Apodemia_mejicanus"
If we use [A-Z] also to match it will match the upper case letter and replace with blank ("") as in the OP's str_replace_all
data
str1 <- "BLCU142-09|Apodemia_mejicanus"
You can always choose to _extract rather than _remove:
s <- "BLCU142-09|Apodemia_mejicanus"
stringr::str_extract(s,"[[:alpha:]_]+$")
## [1] "Apodemia_mejicanus"
Depending on how permissive you want to be, you could also use [[:alpha:]]+_[[:alpha:]]+ as your target.
I would keep it simple:
substring(my_string, regexpr("|", my_string, fixed = TRUE) + 1L)
Here are some examples from my data:
a <-c("sp|Q9Y6W5|","sp|Q9HB90|,sp|Q9NQL2|","orf|NCBIAAYI_c_1_1023|",
"orf|NCBIACEN_c_10_906|,orf|NCBIACEO_c_5_1142|",
"orf|NCBIAAYI_c_258|,orf|aot172_c_6_302|,orf|aot180_c_2_405|")
For a: The individual strings can contain even more entries of "sp|" and "orf"
The results have to be like this:
[1] "sp|Q9Y6W5" "sp|Q9HB90,sp|Q9NQL2" "orf|NCBIAAYI_c_1_1023"
"orf|NCBIACEN_c_10_906,orf|NCBIACEO_c_5_1142"
"orf|NCBIAAYI_c_258,orf|aot172_c_6_302,orf|aot180_c_2_405"
So the aim is to remove the last "|" for each "sp|" and "orf|" entry. It seems that "|" is a special challenge because it is a metacharacter in regular expressions. Furthermore, the length and composition of the "orf|" entries varying a lot. The only things they have in common is "orf|" or "sp|" at the beginning and that "|" is on the last position. I tried different things with gsub() but also with the stringr package or regexpr() or [:punct:], but nothing really worked. Maybe it was just the wrong combination.
We can use gsub to match the | that is followed by a , or is at the end ($) of the string and replace with blank ("")
gsub("[|](?=(,|$))", "", a, perl = TRUE)
#[1] "sp|Q9Y6W5"
#[2] "sp|Q9HB90,sp|Q9NQL2"
#[3] "orf|NCBIAAYI_c_1_1023"
#[4] "orf|NCBIACEN_c_10_906,orf|NCBIACEO_c_5_1142"
#[5] "orf|NCBIAAYI_c_258,orf|aot172_c_6_302,orf|aot180_c_2_405"
Or we split by ,', remove the last character withsubstr, andpastethelist` elements together
sapply(strsplit(a, ","), function(x) paste(substr(x, 1, nchar(x)-1), collapse=","))
An easy alternative that might work. You need to escape the "|" using "\\|".
# Input
a <-c("sp|Q9Y6W5|","sp|Q9HB90|,sp|Q9NQL2|","orf|NCBIAAYI_c_1_1023|",
"orf|NCBIACEN_c_10_906|,orf|NCBIACEO_c_5_1142|",
"orf|NCBIAAYI_c_258|,orf|aot172_c_6_302|,orf|aot180_c_2_405|")
# Expected output
b <- c("sp|Q9Y6W5", "sp|Q9HB90,sp|Q9NQL2", "orf|NCBIAAYI_c_1_1023" ,
"orf|NCBIACEN_c_10_906,orf|NCBIACEO_c_5_1142" ,
"orf|NCBIAAYI_c_258,orf|aot172_c_6_302,orf|aot180_c_2_405")
res <- gsub("\\|,", ",", gsub("\\|$", "", a))
all(res == b)
#[1] TRUE
You could construct a single regex call to gsub, but this is simple and easy to understand. The inner gsub looks for | and the end of the string and removes it. The outer gsub looks for ,| and replaces with ,.
You do not have to use a PCRE regex here as all you need can be done with the default TRE regex (if you specify perl=TRUE, the pattern is compiled with a PCRE regex engine and is sometimes slower than TRE default regex engine).
Here is the single simple gsub call:
gsub("\\|(,|$)", "\\1", a)
See the online R demo. No lookarounds are really necessary, as you see.
Pattern details
\\| - a literal | symbol (because if you do not escape it or put into a bracket expression it will denote an alternation operator, see the line below)
(,|$) - a capturing group (referenced to with \1 from the replacement pattern) matching either of the two alternatives:
, - a comma
| - or (the alternation operator)
$ - end of string anchor.
The \1 in the replacement string tells the regex engine to insert the contents stored in the capturing group #1 back into the resulting string (so, the commas are restored that way where necessary).
I have a column of a dataframe in R like this:
names <- data.frame(name=c("ABC", "ABC-D", "ABCD-"))
I would like to remove the hyphen at the end of the strings while maintaining the hyphen in the middle of them. I've tried a few expressions like:
names$name <- gsub("+-\\w", "", names$name)
# the desired output is "ABC", "ABC-D", and "ABCD", respectively
While several combinations remove the hyphens entirely, I'm not sure how to specify the string boundary and the hyphen together.
Thanks!
Try :
gsub("\\-$", "", names$name)
# [1] "ABC" "ABC-D" "ABCD"
$ tells R that the (escaped) hyphen is at the end of the word
Although, as the - is placed first in the regex you don't need to escape it so this works too:
gsub("-$", "", names$name)
#[1] "ABC" "ABC-D" "ABCD"