The string is as shown below:
s <- "12N10-3A 12N10-3A-1 12N10-3A-2 YB10L-A2"
I can get the strings except from second one.
gsub("\\s.*","",s) #12N10-3A
gsub(".*\\s","",s) #YB10L-A2
gsub(".*\\s.*\\s(.*).*\\s(.*)","\\1",s) #12N10-3A-2
How to get the second string from s and what's short approach for each code line? I tried what I learnt on regex101.com
We can use stri_extract_last from stringi
library(stringi)
stri_extract_last(s, regex = '\\S+')
#[1] "YB10L-A2"
Or use word from stringr
library(stringr)
word(s, 4)
#[1] "YB10L-A2"
Just use strsplit:
items <- strsplit(s, "\\s+")[[1]]
If you want to access the last item, then just use:
items[4]
[1] "YB10L-A2"
If you really wanted to isolate the last term using sub, then here is one way:
sub(".*\\s+", "", s)
Related
text <- c('d__Viruses|f__Closteroviridae|g__Closterovirus|s__Citrus_tristeza_virus',
'd__Viruses|o__Tymovirales|f__Alphaflexiviridae|g__Mandarivirus|s__Citrus_yellow_vein_clearing_virus',
'd__Viruses|o__Ortervirales|f__Retroviridae|s__Columba_palumbus_retrovirus')
I have tried but failed:
str_extract(text, pattern = 'f.*\\|')
How can I get
f__Closteroviridae
f__Alphaflexiviridae
f__Retroviridae
Any help will be high appreciated!
Make the regex non-greedy and since you don't want "|" in final output use positive lookahead.
stringr::str_extract(text, 'f.*?(?=\\|)')
#[1] "f__Closteroviridae" "f__Alphaflexiviridae" "f__Retroviridae"
In base R, we can use sub :
sub('.*(f_.*?)\\|.*', '\\1', text)
#[1] "f__Closteroviridae" "f__Alphaflexiviridae" "f__Retroviridae"
For a base R solution, I would use regmatches along with gregexpr:
m <- gregexpr("\\bf__[^|]+", text)
as.character(regmatches(text, m))
[1] "f__Closteroviridae" "f__Alphaflexiviridae" "f__Retroviridae"
The advantage of using gregexpr as above is that should an input contain more than one f__ matching term, we could also capture it. For example:
x <- 'd__Viruses|f__Closteroviridae|g__Closterovirus|f__some_virus'
m <- gregexpr("\\bf__[^|]+", x)
regmatches(x, m)[[1]]
[1] "f__Closteroviridae" "f__some_virus"
Data:
text <- c('d__Viruses|f__Closteroviridae|g__Closterovirus|s__Citrus_tristeza_virus',
'd__Viruses|o__Tymovirales|f__Alphaflexiviridae|g__Mandarivirus|s__Citrus_yellow_vein_clearing_virus',
'd__Viruses|o__Ortervirales|f__Retroviridae|s__Columba_palumbus_retrovirus')
I have a string like word_string. What I want is Word_String. If I use the function str_to_title from stringr, what I get is Word_string. It does not capitalize the second word.
Does anyone know any elegant way to achieve that with stringr? Thanks!
Here is a base R option using sub:
input <- "word_string"
output <- gsub("(?<=^|_)([a-z])", "\\U\\1", input, perl=TRUE)
output
[1] "Word_String"
The regex pattern used matches and captures any lowercase letter [a-z] which is preceded by either the start of the string (i.e. it's the first letter) or an underscore. Then, we replace with the uppercase version of that single letter. Note that the \U modifier to change to uppercase is a Perl extension, so we must use sub in Perl mode.
Can also use to_any_case from snakecase
library(snakecase)
to_any_case(str1, "title", sep_out = "_")
#[1] "Word_String"
data
str1 <- "word_string"
This is obviously overly complicating but another base possibility:
test <- "word_string"
paste0(unlist(lapply(strsplit(test, "_"),function(x)
paste0(toupper(substring(x,1,1)),
substring(x,2,nchar(x))))),collapse="_")
[1] "Word_String"
You could first use gsub to replace "_" by " " and apply the str_to_title function
Then use gsub again to change it back to your format
x <- str_to_title(gsub("_"," ","word_string"))
gsub(" ","_",x)
Hi have data which contains two or more dots. My requirement is to get string from first to second dot.
E.g string <- "abcd.vdgd.dhdsg"
Result expected =vdgd
I have used
pt <-strapply(string, "\\.(.*)\\.", simplify = TRUE)
which is giving correct data but for string having more than two dots its not working as expected.
e.g string <- "abcd.vdgd.dhdsg.jsgs"
its giving dhdsg.jsgs but expected is vdgd
Could anyone help me.
Thanks & Regards,
In base R we can use strsplit
ss <- "abcd.vdgd.dhdsg"
unlist(strsplit(ss, "\\."))[2]
#[1] "vdgd"
Or using gregexpr with regmatches
unlist(regmatches(ss, gregexpr("[^\\.]+", ss)))[2]
#[1] "vdgd"
Or using gsub (thanks #TCZhang)
gsub("^.+?\\.(.+?)\\..*$", "\\1", ss)
#[1] "vdgd"
Another option:
string <- "abcd.vdgd.dhdsg.jsgs"
library(stringr)
str_extract(string = string, pattern = "(?<=\\.).*?(?=\\.)")
[1] "vdgd"
I like this one because the str_extract function will return the first instance of the correct pattern, but you could also use str_extract_all to get all instances.
str_extract_all(string = string, pattern = "(?<=\\.).*?(?=\\.)")
[[1]]
[1] "vdgd" "dhdsg"
From here, you could index to get any position between two dots you want.
Another solution with the qdapRegex package:
library(qdapRegex)
ex_between("abcd.vdgd.dhdsg.jsgs", ".", ".")[[1]][1]
# "vdgd"
You can use read.table as well if you wish.Here providing the string as given in your problem and selecting the separator as dot("."), Once the column is converted into a data.frame, you may choose to select whatever column you want to pick(In this case it is column number 2).
read.table(text=string, sep=".",stringsAsFactors = FALSE)[,2]
Output:
> read.table(text=string, sep=".",stringsAsFactors = FALSE)[,2]
[1] "vdgd"
Here is a fun easy way via stringr
stringr::word(string, 2, sep = '\\.')
Here are two options that are vectorized over the input string vector:
You can try tstrsplit from data.table, which is vectorized over string:
> string <- c("abcd.vdgd.dhdsg", "abcd.vdgd.dhdsg.jsgs")
> tstrsplit(string, '.', fixed = TRUE)[[2]]
[1] "vdgd" "vdgd"
or regex:
> sub('.*?\\.(.*?)\\..*', '\\1', string)
[1] "vdgd" "vdgd"`
I'm trying to find the first matching string from a vector in a long string. I have for example a example_string <- 'LionabcdBear1231DogextKittyisananimalTurtleisslow' and a matching_vector<- c('Turtle',Dog') Now I want that it returns 'Dog' as this is the first substring in the matching_vector that we see in the example string: LionabcdBear1231DogextKittyisananimalTurtleisslow
I already tried pmatch(example_string,matching_vector) but it doesn't work. Obviously as it doesn't work with substrings...
Thanks!
Tim
Is the following solution working for you?
example_string <- 'LionabcdBear1231DogextKittyisananimalTurtleisslow'
matching_vector<- c('Turtle','Dog')
match_ids <- sapply(matching_vector, function(x) regexpr(x ,example_string))
result <- names(match_ids)[which.min(match_ids)]
> result
[1] "Dog"
We can use stri_match_first from stringi
library(stringi)
stri_match_first(example_string, regex = paste(matching_vector, collapse="|"))
I have the next vector of strings
[1] "/players/playerpage.htm?ilkidn=BRYANPHI01"
[2] "/players/playerpage.htm?ilkidhh=WILLIROB027"
[3] "/players/playerpage.htm?ilkid=THOMPWIL01"
I am looking for a way to retrieve the part of the string that is placed after the equal sign meaning I would like to get a vector like this
[1] "BRYANPHI01"
[2] "WILLIROB027"
[3] "THOMPWIL01"
I tried using substr but for it to work I have to know exactly where the equal sign is placed in the string and where the part i want to retrieve ends
We can use sub to match the zero or more characters that are not a = ([^=]*) followed by a = and replace it with ''.
sub("[^=]*=", "", str1)
#[1] "BRYANPHI01" "WILLIROB027" "THOMPWIL01"
data
str1 <- c("/players/playerpage.htm?ilkidn=BRYANPHI01",
"/players/playerpage.htm?ilkidhh=WILLIROB027",
"/players/playerpage.htm?ilkid=THOMPWIL01")
Using stringr,
library(stringr)
word(str1, 2, sep = '=')
#[1] "BRYANPHI01" "WILLIROB027" "THOMPWIL01"
Using strsplit,
strsplit(str1, "=")[[1]][2]
# [1] "BRYANPHI01"
With Sotos comment to get results as vector:
sapply(str1, function(x){
strsplit(x, "=")[[1]][2]
})
Another solution based on regex, but extracting instead of substituting, which may be more efficient.
I use the stringi package which provides a more powerful regex engine than base R (in particular, supporting look-behind).
str1 <- c("/players/playerpage.htm?ilkidn=BRYANPHI01",
"/players/playerpage.htm?ilkidhh=WILLIROB027",
"/players/playerpage.htm?ilkid=THOMPWIL01")
stri_extract_all_regex(str1, pattern="(?<==).+$", simplify=T)
(?<==) is a look-behind: regex will match only if preceded by an equal sign, but the equal sign will not be part of the match.
.+$ matches everything until the end. You could replace the dot with a more precise symbol if you are confident about the format of what you match. For example, '\w' matches any alphanumeric character, so you could use "(?<==)\\w+$" (the \ must be escaped so you end up with \\w).