[R] converting string vector to integer/numeric vector

[Joshua Wiley]

On Sun, Sep 5, 2010 at 8:36 AM, rajesh j <akshay.rajesh at gmail.com> wrote:
> No, the examples dont cover it...if i have
> dat <- list(INT = c("1","2","3"),
>             NUM = c("2.34","4.56","6.78"),
>             INT = c("4", "5", "6"),
>             NUM = c("3.44"))
>
> I need to do a which on INT[0],NUM[0],INT[0] and NUM[0]...ie the [0] index
> of all the vectors...
> and test if they hold a value

Ah, alright in which case:

lapply(dat, function(x) {x[1] == "4"})

This lapply()s the little test x[1] == "4" to each element in the list
'dat'.  I am using the [1] index because there is no [0] in R.

>
> On Sun, Sep 5, 2010 at 9:03 PM, Joshua Wiley <jwiley.psych at gmail.com> wrote:
>>
>> On Sun, Sep 5, 2010 at 8:16 AM, rajesh j <akshay.rajesh at gmail.com> wrote:
>> > Hi,
>> > in a way similar to names(dat), can I address a particular index of
>> > every
>> > vector?
>> > like [0] of all the vectors? So that I could do something like,
>> > ints<-which(<required usage>=="x")
>>
>> Not sure I follow you exactly, but you can use which() with any
>> logical test.  Take a look at these examples, are any of them what you
>> mean?
>>
>> example(which)
>>
>> If so (or even before) it would be worth it to read through
>>
>> ?which
>>
>> >
>> > On Sun, Sep 5, 2010 at 8:34 PM, Joshua Wiley <jwiley.psych at gmail.com>
>> > wrote:
>> >>
>> >> Hi Rajesh,
>> >>
>> >> This will work, unfortunately it seems like lapply() drops the names
>> >> before it passes each element of the list which lead to my clumsy work
>> >> around using which().  I'm sure there are other ways.
>> >>
>> >> dat <- list(INT = c("1","2","3"),
>> >>            NUM = c("2.34","4.56","6.78"),
>> >>            INT = c("4", "5", "6"),
>> >>            NUM = c("3.44"))
>> >>
>> >> ints <- which(names(dat)=="INT")
>> >> nums <- which(names(dat)=="NUM")
>> >>
>> >> dat[ints] <- lapply(dat[ints], as.integer)
>> >> dat[nums] <- lapply(dat[nums], as.numeric)
>> >>
>> >> str(dat)
>> >>
>> >> Cheers,
>> >>
>> >> Josh
>> >>
>> >> On Sun, Sep 5, 2010 at 6:33 AM, rajesh j <akshay.rajesh at gmail.com>
>> >> wrote:
>> >> > The string vector actually comes as a part of a list, and the vector
>> >> > is
>> >> > named "int", and the numbers are strings. I then have to make it a
>> >> > vector
>> >> > that is still called "int" and has 4,5,6 etc. the types are either
>> >> > integer
>> >> > or numeric. The number of items in the vector is unknown.
>> >> >
>> >> > here's an example,
>> >> >
>> >> > a list has vectors
>> >> >
>> >> > INT
>> >> > "2"
>> >> > "3"
>> >> > "4"
>> >> >
>> >> > NUM
>> >> > "2.37"
>> >> > "4.56"
>> >> >
>> >> >
>> >> >
>> >> > On Sun, Sep 5, 2010 at 6:56 PM, David Winsemius
>> >> > <dwinsemius at comcast.net>wrote:
>> >> >
>> >> >>
>> >> >> On Sep 5, 2010, at 9:22 AM, rajesh j wrote:
>> >> >>
>> >> >> for e.g., I get the following as a string vector
>> >> >> "int" "4" "5" "6"
>> >> >> after reading the first element, I have to convert this to a integer
>> >> >> vector
>> >> >>
>> >> >>
>> >> >>
>> >> >> But what is the right answer?  And what number of items are possble
>> >> >> per
>> >> >> line?  And what are the other possible type identifiers? We need an
>> >> >> example
>> >> >> that has enough complexity to allow testing.
>> >> >>
>> >> >> --
>> >> >> David.
>> >> >>
>> >> >>
>> >> >>
>> >> >> On Sun, Sep 5, 2010 at 6:44 PM, David Winsemius
>> >> >> <dwinsemius at comcast.net>wrote:
>> >> >>
>> >> >>>
>> >> >>> On Sep 5, 2010, at 8:48 AM, rajesh j wrote:
>> >> >>>
>> >> >>>  Hi,
>> >> >>>>
>> >> >>>> Is it possible to convert a string vector to integer or numeric
>> >> >>>> vector?
>> >> >>>> In
>> >> >>>> my situation I receive data in a string vector and have to convert
>> >> >>>> it
>> >> >>>> based
>> >> >>>> on a given type.
>> >> >>>>
>> >> >>>
>> >> >>> Can you give an example? I don't understand either what sort of
>> >> >>> conversion
>> >> >>> you desire or what you mean by "convert it based on a given type."
>> >> >>>
>> >> >>> There are a couple of function you may want to consider but I am
>> >> >>> having
>> >> >>> difficulty convincing myself they answer the problem posed:
>> >> >>>
>> >> >>> ?charToRaw
>> >> >>> ?stroi
>> >> >>>
>> >> >>> > strtoi(charToRaw("123 this is a string"), base=16)   # convert to
>> >> >>> decimal ASCII
>> >> >>>  [1]  49  50  51  32 116 104 105 115  32 105 115  32  97  32 115
>> >> >>> 116
>> >> >>> 114
>> >> >>> 105 110 103
>> >> >>>
>> >> >>> --
>> >> >>>
>> >> >>> David Winsemius, MD
>> >> >>> West Hartford, CT
>> >> >>>
>> >> >>>
>> >> >>
>> >> >>
>> >> >> --
>> >> >> Rajesh.J
>> >> >>
>> >> >>
>> >> >>
>> >> >>  David Winsemius, MD
>> >> >> West Hartford, CT
>> >> >>
>> >> >>
>> >> >
>> >> >
>> >> > --
>> >> > Rajesh.J
>> >> >
>> >> >        [[alternative HTML version deleted]]
>> >> >
>> >> > ______________________________________________
>> >> > R-help at 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.
>> >> >
>> >>
>> >>
>> >>
>> >> --
>> >> Joshua Wiley
>> >> Ph.D. Student, Health Psychology
>> >> University of California, Los Angeles
>> >> http://www.joshuawiley.com/
>> >
>> >
>> >
>> > --
>> > Rajesh.J
>> >
>> >
>> >
>>
>>
>>
>> --
>> Joshua Wiley
>> Ph.D. Student, Health Psychology
>> University of California, Los Angeles
>> http://www.joshuawiley.com/
>
>
>
> --
> Rajesh.J
>
>
>



-- 
Joshua Wiley
Ph.D. Student, Health Psychology
University of California, Los Angeles
http://www.joshuawiley.com/