Re: [R] Differenciate numbers from reference for rows
On Sat, Oct 30, 2010 at 9:43 AM, David Winsemius wrote:
>
> On Oct 30, 2010, at 8:42 AM, Gabor Grothendieck wrote:
>
>> On Fri, Oct 29, 2010 at 6:54 PM, M.Ribeiro
>> wrote:
>>>
>>> So, I am having a tricky reference file to extract information from.
>>>
>>> The format of the file is
>>>
>>> x 1 + 4 * 3 + 5 + 6 + 11 * 0.5
>>>
>>> So, the elements that are not being multiplied (1, 5 and 6) and the
>>> elements
>>> before the multiplication sign (4 and 11) means actually the reference
>>> for
>>> the row in a matrix where I need to extract the element from.
>>>
>>> The numbers after the multiplication sign are regular numbers
>>> Ex:
>>>
x<-matrix(20:35)
>>>
>>> I would like to read the rows 1,4,5,6 and 11 and sum then. However the
>>> numbers in the elements row 4 and 11 are multiplied by 3 and 0.5
>>>
>>> So it would be
>>> 20 + 23 * 3 + 24 + 25 + 30 * 0.5.
>>>
>>> And I have this format in different files so I can't do all by hand.
>>> Can anybody help me with a script that can differentiate this?
>>
>>
>> I assume that every number except for the second number in the pattern
>> number * number is to be replaced by that row number in x. Try this.
>> We define a regular expression which matches the first number ([0-9]+)
>> of each potential pair and optionally (?) spaces ( *) a star (\\*),
>> more spaces ( *) and digits [0-9.]+ passing the first and second
>> backreferences (matches to the parenthesized portions of the regular
>> expression) to f and inserting the output of f where the matches had
>> been.
>>
>> library(gsubfn)
>> f <- function(a, b) paste(x[as.numeric(a)], b)
>> s2 <- gsubfn("([0-9]+)( *\\* *[0-9.]+)?", f, s)
>>
>> If the objective is to then perform the calculation that that
>> represents then try this:
>> sapply(s2, function(x) eval(parse(text = x)))
>>
>> For example,
>>
>>> s <- c("1 + 4 * 3 + 5 + 6 + 11 * 0.5", "1 + 4 * 3 + 5 + 6 + 11 * 0.5")
>>> x <- matrix(20:35)
>>> f <- function(a, b) paste(x[as.numeric(a)], b)
>>> s2 <- gsubfn("([0-9]+)( *\\* *[0-9.]+)?", f, s)
>>> s2
>>
>> [1] "20 + 23 * 3 + 24 + 25 + 30 * 0.5" "20 + 23 * 3 + 24 + 25 + 30
>> * 0.5"
>>>
>>> sapply(s2, function(x) eval(parse(text = x)))
>>
>> 20 + 23 * 3 + 24 + 25 + 30 * 0.5 20 + 23 * 3 + 24 + 25 + 30 *
>> 0.5
>> 153 153
>>
>> For more see the gsubfn home page at http://gsubfn.googlecode.com
>
>
> I am scratching my head regarding the gsubfn workings. It appears that as
> gsubfn moves across the input strings that it will either match just
> "[0-9+]" or it will match "[0-9+] *\\* *[0-9.]+?".
In the regular expression
"([0-9]+)( *\\* *[0-9.]+)?"
it matches the first (...) and then the (...)? part. ? means 0 or 1
occurrences so it can match by matching the content or if that is not
possible it will match the empty string.
>
> In either case the match will do a lookup in x[] for the first match using
> the "a" index, and if there is a match for the second position assigned to
> "*b" then that x[a] will be followed by "*b" and is therefore destined to
> be multiplied by "b". I cannot quite figure out how the NULL value gets
> not-matched to the second back-reference and then doesn't screw up the f()
> function by only providing one argument to a two argument function. Maybe
> it's due to this? (So can you comment on how optional back-references return
> values?)
(...)? says to match 0 or 1 occurrences of the ... expression. Iif
(...) does not match then (...)? will be successful in matching the
empty string. The function is always called with two arguments. Try
this:
> s <- "1 + 4 * 3 + 5 + 6 + 11 * 0.5"
> g <- function(a, b) sprintf("", a, b)
> gsubfn("([0-9]+)( *\\* *[0-9.]+)?", g, s)
[1] " + + +
+ "
--
Statistics & Software Consulting
GKX Group, GKX Associates Inc.
tel: 1-877-GKX-GROUP
email: ggrothendieck at gmail.com
__
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
Re: [R] Differenciate numbers from reference for rows
On Oct 30, 2010, at 8:42 AM, Gabor Grothendieck wrote:
On Fri, Oct 29, 2010 at 6:54 PM, M.Ribeiro
wrote:
So, I am having a tricky reference file to extract information from.
The format of the file is
x 1 + 4 * 3 + 5 + 6 + 11 * 0.5
So, the elements that are not being multiplied (1, 5 and 6) and the
elements
before the multiplication sign (4 and 11) means actually the
reference for
the row in a matrix where I need to extract the element from.
The numbers after the multiplication sign are regular numbers
Ex:
x<-matrix(20:35)
I would like to read the rows 1,4,5,6 and 11 and sum then. However
the
numbers in the elements row 4 and 11 are multiplied by 3 and 0.5
So it would be
20 + 23 * 3 + 24 + 25 + 30 * 0.5.
And I have this format in different files so I can't do all by hand.
Can anybody help me with a script that can differentiate this?
I assume that every number except for the second number in the pattern
number * number is to be replaced by that row number in x. Try this.
We define a regular expression which matches the first number ([0-9]+)
of each potential pair and optionally (?) spaces ( *) a star (\\*),
more spaces ( *) and digits [0-9.]+ passing the first and second
backreferences (matches to the parenthesized portions of the regular
expression) to f and inserting the output of f where the matches had
been.
library(gsubfn)
f <- function(a, b) paste(x[as.numeric(a)], b)
s2 <- gsubfn("([0-9]+)( *\\* *[0-9.]+)?", f, s)
If the objective is to then perform the calculation that that
represents then try this:
sapply(s2, function(x) eval(parse(text = x)))
For example,
s <- c("1 + 4 * 3 + 5 + 6 + 11 * 0.5", "1 + 4 * 3 + 5 + 6 + 11 *
0.5")
x <- matrix(20:35)
f <- function(a, b) paste(x[as.numeric(a)], b)
s2 <- gsubfn("([0-9]+)( *\\* *[0-9.]+)?", f, s)
s2
[1] "20 + 23 * 3 + 24 + 25 + 30 * 0.5" "20 + 23 * 3 + 24 +
25 + 30 * 0.5"
sapply(s2, function(x) eval(parse(text = x)))
20 + 23 * 3 + 24 + 25 + 30 * 0.5 20 + 23 * 3 + 24 + 25 +
30 * 0.5
153 153
For more see the gsubfn home page at http://gsubfn.googlecode.com
I am scratching my head regarding the gsubfn workings. It appears that
as gsubfn moves across the input strings that it will either match
just "[0-9+]" or it will match "[0-9+] *\\* *[0-9.]+?".
In either case the match will do a lookup in x[] for the first match
using the "a" index, and if there is a match for the second position
assigned to "*b" then that x[a] will be followed by "*b" and is
therefore destined to be multiplied by "b". I cannot quite figure out
how the NULL value gets not-matched to the second back-reference and
then doesn't screw up the f() function by only providing one argument
to a two argument function. Maybe it's due to this? (So can you
comment on how optional back-references return values?)
> paste("a", NULL)
[1] "a "
Furthermore, somehow (and this is further functiona magic I am
missing) these results are concatenated in a string, and then
evaluated, a step which I do get.
--
David Winsemius, MD
West Hartford, CT
__
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
Re: [R] Differenciate numbers from reference for rows
On Fri, Oct 29, 2010 at 6:54 PM, M.Ribeiro wrote:
>
> So, I am having a tricky reference file to extract information from.
>
> The format of the file is
>
> x 1 + 4 * 3 + 5 + 6 + 11 * 0.5
>
> So, the elements that are not being multiplied (1, 5 and 6) and the elements
> before the multiplication sign (4 and 11) means actually the reference for
> the row in a matrix where I need to extract the element from.
>
> The numbers after the multiplication sign are regular numbers
> Ex:
>
>> x<-matrix(20:35)
>> x
> [,1]
> [1,] 20
> [2,] 21
> [3,] 22
> [4,] 23
> [5,] 24
> [6,] 25
> [7,] 26
> [8,] 27
> [9,] 28
> [10,] 29
> [11,] 30
> [12,] 31
> [13,] 32
> [14,] 33
> [15,] 34
> [16,] 35
>
> I would like to read the rows 1,4,5,6 and 11 and sum then. However the
> numbers in the elements row 4 and 11 are multiplied by 3 and 0.5
>
> So it would be
> 20 + 23 * 3 + 24 + 25 + 30 * 0.5.
>
> And I have this format in different files so I can't do all by hand.
> Can anybody help me with a script that can differentiate this?
I assume that every number except for the second number in the pattern
number * number is to be replaced by that row number in x. Try this.
We define a regular expression which matches the first number ([0-9]+)
of each potential pair and optionally (?) spaces ( *) a star (\\*),
more spaces ( *) and digits [0-9.]+ passing the first and second
backreferences (matches to the parenthesized portions of the regular
expression) to f and inserting the output of f where the matches had
been.
library(gsubfn)
f <- function(a, b) paste(x[as.numeric(a)], b)
s2 <- gsubfn("([0-9]+)( *\\* *[0-9.]+)?", f, s)
If the objective is to then perform the calculation that that
represents then try this:
sapply(s2, function(x) eval(parse(text = x)))
For example,
> s <- c("1 + 4 * 3 + 5 + 6 + 11 * 0.5", "1 + 4 * 3 + 5 + 6 + 11 * 0.5")
> x <- matrix(20:35)
> f <- function(a, b) paste(x[as.numeric(a)], b)
> s2 <- gsubfn("([0-9]+)( *\\* *[0-9.]+)?", f, s)
> s2
[1] "20 + 23 * 3 + 24 + 25 + 30 * 0.5" "20 + 23 * 3 + 24 + 25
+ 30 * 0.5"
> sapply(s2, function(x) eval(parse(text = x)))
20 + 23 * 3 + 24 + 25 + 30 * 0.5 20 + 23 * 3 + 24 + 25 + 30 * 0.5
153 153
For more see the gsubfn home page at http://gsubfn.googlecode.com
--
Statistics & Software Consulting
GKX Group, GKX Associates Inc.
tel: 1-877-GKX-GROUP
email: ggrothendieck at gmail.com
__
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
Re: [R] Differenciate numbers from reference for rows
On Oct 29, 2010, at 11:16 PM, Dennis Murphy wrote: Hi: x <- matrix(20:35, ncol = 1) u <- c(1, 4, 5, 6, 11) # 'x values' m <- c(1, 3, 1, 1, 0.5) # Function to compute the inner product of the multipliers with the extracted # elements of x determined by u f <- function(mat, inputs, mults) crossprod(mat[inputs], mults) f(x, u, mults = c(1, 3, 1, 1, 0.5)) [,1] [1,] 153 20 + 23 * 3 + 24 + 25 + 30 * 0.5 [1] 153 The function is flexible enough to allow you to play with the input matrix (although a vector would also work), the 'observation vector' inputs and the set of multipliers. Here's one way (not necessarily the most efficient): uv <- matrix(sample(1:15, 25, replace = TRUE), ncol = 5) uv # like an X matrix, where each row provides the input values of the vars [,1] [,2] [,3] [,4] [,5] [1,] 128 11 10 15 [2,] 15 11 14 148 [3,]484 10 12 [4,] 105217 [5,] 11491 11 # Apply the function f to each row of uv: apply(uv, 1, function(y) f(x, y, mults = c(1, 3, 1, 1, 0.5))) [1] 188.0 203.5 171.5 155.0 162.0 The direct matrix version: crossprod(t(matrix(x[uv], ncol = 5)), c(1, 3, 1, 1, 0.5)) [,1] [1,] 188.0 [2,] 203.5 [3,] 171.5 [4,] 155.0 [5,] 162.0 Notice that the apply() call returns a vector whereas crossprod() returns a matrix. x[uv] selects the x values associated with the indices in uv and returns a vector in column-major order. The crossprod() call transposes the reshaped x[uv] and then 'matrix' multiplies it by the vector c(1, 3, 1, 1, 0.5). HTH, Dennis On Fri, Oct 29, 2010 at 3:54 PM, M.Ribeiro wrote: So, I am having a tricky reference file to extract information from. The format of the file is x 1 + 4 * 3 + 5 + 6 + 11 * 0.5 I saw the beginning of this task as parsing to extract the digits from a character string (possibly decimal digits in the case of the third and seventh positions) delimited by + and *: library(gsubfn) > x <- "1 + 4 * 3 + 5 + 6 + 11 * 0.5" xin <- readLines(textConnection(x)) xp <- strapply(xin, "^(\\d+) \\+ (\\d+) \\* (\\d+\\.*\\d*) \\+ (\\d +) \\+ (\\d+) \\+ (\\d+) \\* (\\d+\\.*\\d*)", c) sapply(xp, as.numeric) [,1] [1,] 1.0 [2,] 4.0 [3,] 3.0 [4,] 5.0 [5,] 6.0 [6,] 11.0 [7,] 0.5 -- David So, the elements that are not being multiplied (1, 5 and 6) and the elements before the multiplication sign (4 and 11) means actually the reference for the row in a matrix where I need to extract the element from. The numbers after the multiplication sign are regular numbers Ex: x<-matrix(20:35) x [,1] [1,] 20 [2,] 21 [3,] 22 [4,] 23 [5,] 24 [6,] 25 [7,] 26 [8,] 27 [9,] 28 [10,] 29 [11,] 30 [12,] 31 [13,] 32 [14,] 33 [15,] 34 [16,] 35 I would like to read the rows 1,4,5,6 and 11 and sum then. However the numbers in the elements row 4 and 11 are multiplied by 3 and 0.5 So it would be 20 + 23 * 3 + 24 + 25 + 30 * 0.5. And I have this format in different files so I can't do all by hand. Can anybody help me with a script that can differentiate this? Thanks -- View this message in context: http://r.789695.n4.nabble.com/Differenciate-numbers-from-reference-for-rows-tp3019853p3019853.html Sent from the R help mailing list archive at Nabble.com. __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. [[alternative HTML version deleted]] __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. David Winsemius, MD West Hartford, CT __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
Re: [R] Differenciate numbers from reference for rows
Hi: x <- matrix(20:35, ncol = 1) u <- c(1, 4, 5, 6, 11) # 'x values' m <- c(1, 3, 1, 1, 0.5) # Function to compute the inner product of the multipliers with the extracted # elements of x determined by u f <- function(mat, inputs, mults) crossprod(mat[inputs], mults) f(x, u, mults = c(1, 3, 1, 1, 0.5)) [,1] [1,] 153 20 + 23 * 3 + 24 + 25 + 30 * 0.5 [1] 153 The function is flexible enough to allow you to play with the input matrix (although a vector would also work), the 'observation vector' inputs and the set of multipliers. Here's one way (not necessarily the most efficient): uv <- matrix(sample(1:15, 25, replace = TRUE), ncol = 5) uv # like an X matrix, where each row provides the input values of the vars [,1] [,2] [,3] [,4] [,5] [1,] 128 11 10 15 [2,] 15 11 14 148 [3,]484 10 12 [4,] 105217 [5,] 11491 11 # Apply the function f to each row of uv: apply(uv, 1, function(y) f(x, y, mults = c(1, 3, 1, 1, 0.5))) [1] 188.0 203.5 171.5 155.0 162.0 The direct matrix version: crossprod(t(matrix(x[uv], ncol = 5)), c(1, 3, 1, 1, 0.5)) [,1] [1,] 188.0 [2,] 203.5 [3,] 171.5 [4,] 155.0 [5,] 162.0 Notice that the apply() call returns a vector whereas crossprod() returns a matrix. x[uv] selects the x values associated with the indices in uv and returns a vector in column-major order. The crossprod() call transposes the reshaped x[uv] and then 'matrix' multiplies it by the vector c(1, 3, 1, 1, 0.5). HTH, Dennis On Fri, Oct 29, 2010 at 3:54 PM, M.Ribeiro wrote: > > So, I am having a tricky reference file to extract information from. > > The format of the file is > > x 1 + 4 * 3 + 5 + 6 + 11 * 0.5 > > So, the elements that are not being multiplied (1, 5 and 6) and the > elements > before the multiplication sign (4 and 11) means actually the reference for > the row in a matrix where I need to extract the element from. > > The numbers after the multiplication sign are regular numbers > Ex: > > > x<-matrix(20:35) > > x > [,1] > [1,] 20 > [2,] 21 > [3,] 22 > [4,] 23 > [5,] 24 > [6,] 25 > [7,] 26 > [8,] 27 > [9,] 28 > [10,] 29 > [11,] 30 > [12,] 31 > [13,] 32 > [14,] 33 > [15,] 34 > [16,] 35 > > I would like to read the rows 1,4,5,6 and 11 and sum then. However the > numbers in the elements row 4 and 11 are multiplied by 3 and 0.5 > > So it would be > 20 + 23 * 3 + 24 + 25 + 30 * 0.5. > > And I have this format in different files so I can't do all by hand. > Can anybody help me with a script that can differentiate this? > Thanks > -- > View this message in context: > http://r.789695.n4.nabble.com/Differenciate-numbers-from-reference-for-rows-tp3019853p3019853.html > Sent from the R help mailing list archive at Nabble.com. > > __ > R-help@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide > http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. > [[alternative HTML version deleted]] __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
[R] Differenciate numbers from reference for rows
So, I am having a tricky reference file to extract information from. The format of the file is x 1 + 4 * 3 + 5 + 6 + 11 * 0.5 So, the elements that are not being multiplied (1, 5 and 6) and the elements before the multiplication sign (4 and 11) means actually the reference for the row in a matrix where I need to extract the element from. The numbers after the multiplication sign are regular numbers Ex: > x<-matrix(20:35) > x [,1] [1,] 20 [2,] 21 [3,] 22 [4,] 23 [5,] 24 [6,] 25 [7,] 26 [8,] 27 [9,] 28 [10,] 29 [11,] 30 [12,] 31 [13,] 32 [14,] 33 [15,] 34 [16,] 35 I would like to read the rows 1,4,5,6 and 11 and sum then. However the numbers in the elements row 4 and 11 are multiplied by 3 and 0.5 So it would be 20 + 23 * 3 + 24 + 25 + 30 * 0.5. And I have this format in different files so I can't do all by hand. Can anybody help me with a script that can differentiate this? Thanks -- View this message in context: http://r.789695.n4.nabble.com/Differenciate-numbers-from-reference-for-rows-tp3019853p3019853.html Sent from the R help mailing list archive at Nabble.com. __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
