Displaying 20 results from an estimated 10000 matches similar to: "Basic data structures"
2008 Nov 29
2
Using grep() to subset lines of text
I have two vectors, a and b. b is a text file. I want to find in b those
elements of a which occur at the beginning of the line in b. I have the
following code, but it only returns a value for the first value in a, but I
want both. Any ideas please.
a = c(2,3)
b = NULL
b[1] = "aaa 2 aaa"
b[2] = "2 aaa"
b[3] = "3 aaa"
b[4] = "aaa 3 aaa"
2011 Feb 01
3
R string help
Dear R guru:
If I got a variable
aaa<- "up.6.11(16)"
how can I extract 16 out of the bracket?
I could use substr, e.g.
substr(aaa, start=1, stop=2)
[1] "up"
But it needs start and stop, what if my start or stop is not fixed, I
just want the number inside the bracket, how can I achieve this?
Many thanks
yan
2010 May 05
1
extracting a matched string using regexpr
Given a text like
I want to be able to extract a matched regular expression from a piece of
text.
this apparently works, but is pretty ugly
# some html
test<-"</tr><tr><th>88958</th><th>Abcdsef</th><th>67.8S</th><th>68.9\nW</th><th>26m</th>"
# a pattern to extract 5 digits
> pattern<-"[0-9]{5}"
#
2009 Feb 25
3
regexp capturing group in R
Hello,
Newbie question: how do you capture groups in a regexp in R?
Let's say I have txt="blah blah start=20080101 end=20090224".
I'd like to get the two dates start and end.
In Perl, one would say:
my ($start,$end) = ($txt =~ /start=(\d{8}).*end=(\d{8})/);
I've tried:
txt <- "blah blah start=20080101 end=20090224"
m <-
2006 Jul 23
3
RfW 2.3.1: regular expressions to detect pairs of identical word-final character sequences
Dear all
I use R for Windows 2.3.1 on a fully updated Windows XP Home SP2 machine and I have two related regular expression problems.
platform i386-pc-mingw32
arch i386
os mingw32
system i386, mingw32
status
major 2
minor
2010 Feb 18
3
parsing strings between [ ] in columns
Dear all,
I have a data.frame with a column like the x shown below
myDF<-data.frame(cbind(x=c("[[1, 0, 0], [0, 1]]",
"[[1, 1, 0], [0, 1]]","[[1, 0, 0], [1, 1]]",
"[[0, 0, 1], [0, 1]]")))
> myDF
x
1 [[1, 0, 0], [0, 1]]
2 [[1, 1, 0], [0, 1]]
3 [[1, 0, 0], [1, 1]]
4 [[0, 0, 1], [0, 1]]
As you can see my x column is composed of
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
2010 Aug 22
4
how to implement string pattern extraction in R
Hi,
In perl, to get a substring matching a particular pattern can be
implemented like the following example:
$x = "AAAA.txt";
if ($x=~ /(.*?)\.txt/){
$prefix = $1;
}
So how to do the same thing in R?
Can someone provide me the code sample?
Thanks much in advance.
--
Waverley @ Palo Alto
2010 Oct 26
2
Formatting durations
Hi,
I am working with a dataset for sometime and I need some help in parsing
some data.
There is a column called "Duration" which has data like following:
2 minutes => 120
2 min => 120
10 seconds =>10
2 hrs =>7200
2-3 minutes => 150 or 120
5 minutes (when i arrived => 300
Flyby approx 20 sec. => 20
felt like 10 mins but tim => 600
I need to convert them to
2009 Apr 15
2
Split string
> (FICB[,"temp"])
[1] "0.30" "0.55" "0.45" "2.30" "0.45" "0.30" "0.25" "0.30" "0.30"
"1.05" "1.00" "1.00"
[13] "0.30" "0.30" "0.30" "0.55" "0.30" "0.30" "0.30" "0.25" "1.00"
2009 Mar 03
4
regular expression question
can someone show me how to use a regular expression to break the string
at the bottom up into its three components :
(-0.791,-0.263]
(-38,-1.24]
(0.96,2.43]
I tried to use strplit because of my regexpitis ( it's not curable. i've
been to many doctors all over NYC. they tell me there's no cure ) but
it doesn't work because there also dots inside the brackets. Thanks.
2008 Nov 02
5
R newbie: how to replace string/regular expression
Hello;
I am a R newbie and would like to know correct and efficient method for
doing string replacement.
I have a large data set, where I want to replace character "M", "b",
and "K" (currency in Million, Billion and K) to millions. That is
209.7B with (209.7 * 10e6) and 100.00K with (100.00 *1/100)
and etc..
d <- c("120.0M", "11.01m",
2008 Aug 12
2
perl expression question
I have a string such as
fileName<-"Agg.20.20.20-all-01".
All I want to do is pull the "20.20.20" and the "all" as strings.
Obviously, they aren't always those values.
The "20.20.20" can be "30.30.30" but it's always after the . which is
next to the second g in Agg and it's always the same length. The all
might not always be
2006 Sep 25
2
Splitting a character variable into a numeric one and a character one?
Hi All,
I have a data with a variable like this:
Column 1
"123abc"
"12cd34"
"1e23"
...
Now I want to do an operation that can split it into two variables:
Column 1 Column 2 Column 3
"123abc" 123 "abc"
"12cd34" 12 "cd34"
"1e23" 1
2008 Nov 28
3
regexp help needed
Hello,
I have a vector of dates and I would like to grep the year component
from this vector (= all digits
after the last punctuation character)
dates <- c("28.7.08","28.7.2008","28/7/08", "28/7/2008", "28/07/2008",
"28-07-2008", "28-07-08")
the resulting vector should look like
"08" "2008"
2009 Dec 28
3
apply loop - using/providing a data frame to loop over
Hi,
I want to extract individual names from a single string that contains all
names. My problem is not the extraction itself, but the looping over the
extraction start and end points, which I try to realize with apply.
#Say, I have a string with names.
authors=c("Schleyer T, Spallek H, Butler BS, Subramanian S, Weiss D,
Poythress ML, Rattanathikun P, Mueller G")
#Since I only want the
2006 Nov 07
1
Gregexpr - extract results with lapply
Gregexpr - extract results with lapply
Hello,
I need to extract sequences of three upper case letters in a string. In
other words, in this string:
str <-c("ABC", "this WOUld be gOOD")
The result I'm looking for is ABC WOU OOD.
With gregexpr, I can get the position and length of the sequences
gregexpr('[A-Z]{3}',str,perl=TRUE)
[[1]]
[1] 1
2008 Sep 18
3
character position
Hi,
I'm not being able to capture a position of a 'string' in a character
string.
In this example: 'There are 20 species in this grid'
I would like to capture the string (number) after 'are' and before
'species'. Consider they do not change. I wouldn't like to use substr
because stop position may change.
Thanks
Paulo
2010 Feb 08
2
the hat ^ in regular expression
Un texte encapsul? et encod? dans un jeu de caract?res inconnu a ?t? nettoy?...
Nom : non disponible
URL : <https://stat.ethz.ch/pipermail/r-help/attachments/20100208/52a6d080/attachment.pl>
2007 Oct 15
4
Get the last 3 chars of a string
I want to extract the last 3 letters of a string.
So far, I've done this:
> symbol = 'XYZ.VX"
> substr(symbol,nchar(symbol)-2,nchar(symbol))
[1] ".VX"
It works, but the code looks UGLY as hell. Am I missing something? Or
is this the way it's supposed to be?
Thanks,
Sergio
On 10/15/07, pintinho <diego at bpgomes.com> wrote:
>
> Hi everyone,
>