This question already has answers here:
grep using a character vector with multiple patterns
(11 answers)
Find matching strings between two vectors in R
(2 answers)
Closed 5 years ago.
I have a two different vectors
v1 <- c("HelloWorld", "Climate","fooboo","testtesting")
v2 <- c("hello","test")
I want to compare both the vector and need to get "HelloWorld" and "testingtestin".
I used regexpr, but i have'nt get the result.
sapply(v1 , regexpr, v2 , ignore.case=TRUE)
Related
This question already has answers here:
How to calculate the number of occurrence of a given character in each row of a column of strings?
(14 answers)
Count the number of pattern matches in a string
(6 answers)
Closed 2 years ago.
Say I have a strings
seq1 <- "ACTACTGGATGACT"
pattern1 <- "ACT"
What is the best way to find the number of times the pattern is in the sequence, in R? I would like to use a sliding window for loop, but im not clear on the proper way to handle the character strings.
We can use str_count
library(stringr)
str_count(seq1, pattern1)
#[1] 3
This question already has answers here:
string starting with specific pattern
(2 answers)
Filter a vector of strings based on string matching
(4 answers)
Closed 3 years ago.
I have a vector which have following three strings
test <- c("www.example.com/topic/university-admission",
"www.example.com/topic/school-admission",
"www.example.com/college-admission")
I want to extract all the element which have pattern like this "www.example.com/topic/"
One way is just looking at vector and extract as per the index location of that element.
But this will be challenging if vector has length of say 100.
Is there any way to do this using string pattern matching?
test[startsWith(x = test, "www.example.com/topic/")]
# [1] "www.example.com/topic/university-admission" "www.example.com/topic/school-admission"
This question already has answers here:
How to generate all possible combinations of vectors without caring for order?
(2 answers)
Closed 3 years ago.
I have multiple character strings, let's say 'pred_1', 'pred_2' and 'pred_3'. Now I want to get a list with all pairs of the strings. So, the resulting list should contain 'pred_1 pred_2', 'pred_1 pred_3' and 'pred_2 pred_3'. Does anyone know how to automate this for more than three character strings?
An option is combn
combn(v1, 2, simplify = FALSE)
data
v1 <- paste0("pred_", 1:3)
This question already has answers here:
Find all positions of all matches of one vector of values in second vector
(3 answers)
Finding All Positions for Multiple Elements in a Vector
(7 answers)
Closed 4 years ago.
In the following example, there is repeating entries in the second vector. How do I make R to tell me the position of both appearances of 5, please?
match(5, c(1,2,9,5,3,6,7,4,5))
Use the which function:
which(c(1,2,9,5,3,6,7,4,5) == 5)
This question already has answers here:
Trying to return a specified number of characters from a gene sequence in R
(3 answers)
Extracting the last n characters from a string in R
(15 answers)
Closed 5 years ago.
Is there a function in R that I can cut a value in vector.
for example i got this vec:
40754831597
64278107602
64212163451
and each vale in the vec i want to cut so from the number pos 3 to 6 for example and get a new vector look like this
7548
2781
2121
and so on
I don't really get why you would like to do this, but here you go:
# assuming it's a character vector
substring(vec,3,6)
# if it's numeric
substring(as.character(vec),3,6)
#output
#[1] "7548" "2781" "2121"
We can use sub
sub(".{2}(.{4}).*", "\\1", v1)
#[1] "7548" "2781" "2121"
data
v1 <- c(40754831597, 64278107602, 64212163451)