Displaying 20 results from an estimated 10000 matches similar to: "Q. About String indexing"
2005 Oct 28
3
splitting a character field in R
Dear R users,
I have a dataframe with one character field, and I would like to create two
new fields (columns) in my dataset, by spliting the existing character
field into two using an existing substring.
... something that in SAS I could solve e.g. combining substr(which I am
aware exist in R) and "index" for determining the position of the pattern
within the string.
e.g. if my
2009 Sep 25
7
Spliting columns, strings or reg exp returning substrings
Currently as the first column in a data frame I have string values in the format xx_yy - I want to create a new column with just the substring xx (for each row in turn). Three possible ways to do this might be (1) split the string by '_' using strsplit and paste the first of the resulting variables into a new column, but I have been unable to do this for each row of my data frame in turn
1999 Dec 18
1
strsplit does not conform to documentation (PR#379)
Description:
Split the Strings in `x' into substrings according to
the presence of substring `split' within them.
--------------------
> strsplit("acbdefgSPLIThigkilmnSpPqrst","SPLIT")
[[1]]
[1] "acbdefg" "higkilmn" "p" "qrst"
--------------------
Apparently, it will
Split the Strings in `x' into
2009 Apr 10
4
split a character variable into several character variable by a character
Dear Mao Jianfeng,
"r-help-owner" is not the place for help, but:
r-help at r-project.org
(CC-ed here)
In any case, strsplit() does the job, i.e.:
> unlist(strsplit("BCPy01-01", "-"))
[1] "BCPy01" "01"
You can work with the whole variable, like:
splitpop <- strsplit(df1$popcode, "-")
then access the first part with
>
2011 Jun 18
3
how to subtract one string from another in R
Dear R Group
Here is what i am trying to do.. but couldnt figure out how..
string<-"ABC DEFG HIJKLM NOPQ RSTUV WXY"
string1<-substr(string,1,4)
I want to create an R object string 2 ( following the logic shown).. R does
not allow string subtraction.. any suggestions how to achieve this?
string2<-string-string1 (it should now hold "DEFG HIJKLM NOPQ RSTUV WXY"
I
2012 Feb 08
4
"unsparse" a vector
Suppose I have a vector of strings:
c("A1B2","A3C4","B5","C6A7B8")
[1] "A1B2" "A3C4" "B5" "C6A7B8"
where each string is a sequence of <column><value> pairs
(fixed width, in this example both value and name are 1 character, in
reality the column name is 6 chars and value is 2 digits).
I need to
2005 Sep 15
2
Splitting the string at the last sub-string
Hi,
I need to split a string into 2 strings, with the split point defined by the
last occurrence of some substring. I come up with some convoluted code to do
so:
str = "Chance favors the prepared mind"
sub = "e"
y = unlist(strsplit(str,sub))
z = cbind(paste(y[-length(y)], sub, sep="", collapse = ""), y[length(y)]);
y
z
z[1]
z[2]
Is there a simpler way
2009 Dec 09
4
binary string conversion to a vector (PR#14120)
Full_Name: Franc Brglez
Version: R 2.9.1 GUI 1.28 Tiger build 32-bit (5444)
OS: MacOSX -- 10.6.2
Submission from: (NULL) (24.148.163.114)
I am demonstrating what may be a bug or my lack of experience. Please review as
it would help to hear from someone.
MANY THANKS -- Franc Brglez
The function "binS2binV" returns what I consider a wrong value -- see the
terminal output
binS2binV =
2003 May 22
4
grep, gsub, sub have problems with NA values (PR#3078)
In a string context, grep, gsub, sub are improperly treating NA (missing) as
the string "NA", and returning unexpected results
> grep("A", c(NA,"NA"))
[1] 1 2
# expected:
# [1] 2
> gsub("A", "X", c(NA,"NA"))
[1] "NX" "NX"
# expected
# [1] NA "NX"
> sub("A", "X",
2011 Apr 11
1
Getting many substrings but only loading the original string one time.
Hi All,
I'm looking for a way to get many substrings from a longer string and
then stitch them together. But, since the longer string is really, really
long (like 250 MB long), I don't want to do this in a loop and load and
re-load the longer string many times. Does anybody have an idea?
Maybe I could pass in two vectors (the first would have the starting
coordinates, and the second
2004 Mar 24
1
string problems ( grep and regepxr)
Recently working with strings and data
I have found a small problem.
Windows XP
R 1.8.1
Reading data from a "txt file" with readLine.
finding a specific line with "grep" command, all OK.
but here comes the problem...
After finding the correct line(s) i need to find a substring
inside each string.
In this case "tabs" I think it represented by "\t" in the
2008 Oct 29
6
substring/strsplit question
Dear R People:
Here is a toy example:
> x <- c("2E","5W","12H")
> substr(x,2,2)
[1] "E" "W" "2"
>
Sometimes x has 3 elements, sometimes 2. I want to extract the last
element, and then extract the other 1 or 2 elements.
How can I do this, please?
TIA,
Sincerely,
Erin
--
Erin Hodgess
Associate Professor
Department of
2011 Jul 05
2
Stuck ...can't get sapply and xmlTreeParse working
Can't seem to get the code below working. It gets stuck on line 24 inside the
function hm; comments show the line in question. The function hm is called
by sapply and is at the bottom of the code. Other stuff above line 24 works
correctly including the first couple of lines of the function hm. Should I
be using a different apply function or am I doing something wrong with
xmlTreeParse ?
2019 Feb 22
1
Bug: time complexity of substring is quadratic as string size and number of substrings increases
On 2/20/19 7:55 PM, Toby Hocking wrote:
> Update: I have observed that stringi::stri_sub is linear time complexity,
> and it computes the same thing as base::substring. figure
> https://github.com/tdhock/namedCapture-article/blob/master/figure-substring-bug.png
> source:
> https://github.com/tdhock/namedCapture-article/blob/master/figure-substring-bug.R
>
> To me this is a
2003 Jul 21
1
Inconsistent handling of character NA?
[R 1.7.1 on Windows XP Pro]
Since R allows missing values for character variables, why
are NA's not propagated by character manipulation functions?
For example:
> temp <- c("a", NA)
> temp
[1] "a" NA
> is.na(temp)
[1] FALSE TRUE
> paste(temp[1], temp[2])
[1] "a NA"
> substr(temp, 1, 1)
[1] "a" "N"
>
2009 Sep 12
3
the integer of a given location
I have a huge number such as 78923698701
z<-78923698701
I want to find the integer of a given location, for example here, what is
the 2nd number? 8.
Thanks in advance!
--
View this message in context: http://www.nabble.com/the-integer-of-a-given-location-tp25418729p25418729.html
Sent from the R help mailing list archive at Nabble.com.
2011 Sep 29
2
String manipulation with regexpr, got to be a better way
Help-Rs,
I'm doing some string manipulation in a file where I converted a string date in mm/dd/yyyy format and returned the date yyyy.
I've used regexpr (hat tip to Gabor G for a very nice earlier post on this function) in steps (I've un-nested the code and provided it and an example of what I did below. My question is: is there a more efficient way to do this. Specifically is
2012 May 07
2
substr not by position but by symbol
Hi all,
One of my variables looks like this:
.7_-.3_-.2_.9
And this is a character variable. I made this by combining four different
number like .7, -.3, -.2, and .9 using paste function.
Now, I want to go back to original format from this one combined character
variable. For instance, I want to extract 3rd number, -.2, from this
character.
I know I can use substr function, but each position
2006 Jul 17
10
String manipulation and formatting
I'm trying to write a simple function that does the following:
[command] xify(5.2)
[output] XXX.XX
[command] xify(3)
[output] XXX
Any simple solutions (without using python/perl/unix script/...)?
Thanks,
Saghir
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2009 Jul 08
5
R regular expression to extract words with the query string.
Hi,
Is there a way in R to get the string which matches the expression, where
the expression is a substring of the parent string.
Lets say, I have $i <- "transcript:ENST0000112334 pid:ENSP000012345"
What I need is the string "pid:ENSP000012345" from $i using the query
"ENSP".
Appreciate your comments.
Praveen Surendran
School of Medicine and