[R] how to select all columns that contain in any of their rows a partial match for a string?

[Ana Marija]

Thank you so much this worked wonderfully!

On Sat, Oct 5, 2019 at 4:05 PM Rui Barradas <ruipbarradas using sapo.pt> wrote:
>
> Hello,
>
> Please CC the list.
>
> The following code does what you want.
>
> tot <- data.frame(a = c("E10123", "F123", "G4567"),
>                    b = c("a123", "E112345", "b456"))
>
> e10 <- sapply(tot, function(x) grepl("^E10", x))
> e10 <- rowSums(e10) > 0
> e11 <- sapply(tot, function(x) grepl("^E11", x))
> e11 <- rowSums(e11) > 0
>
> tot$newcol <- -9
> tot$newcol[e10] <- 1
> tot$newcol[e11] <- 2
>
>
> On both cases the 2 lines sapply/rowSums can be made one with
>
> rowSums(sapply(...)) > 0
>
>
> Hope this helps,
>
> Rui Barradas
>
> Às 20:52 de 05/10/19, Ana Marija escreveu:
> > Hi Rui,
> >
> > thank you so much for getting back to me.
> >
> > I did what you told me:
> > cols <- sapply(tot, function(x) any(grepl("^E10", x)))
> > a=which(cols)
> >
> > so this gives me name of 49 columns that have that particular string
> >
> > But how do I create a new column in my tot data frame (the column
> > would be called "TD") which has 1 in the row where the subject
> > (designated in the "eid" column) has a string which starts with "E10"
> > and it has 2 if it starts with "E11" and otherwise it is -9.
> >
> >> head(tot)[1:3,1:3]
> >        eid          sex_f31_0_0         year_of_birth_f34_0_0
> > 1 1000017      Female                  1938
> > 2 1000025      Female                  1951
> > 3 1000038        Male                     1961
> >
> > Thanks you so much!
> >
> >
> > On Sat, Oct 5, 2019 at 2:24 PM Rui Barradas <ruipbarradas using sapo.pt> wrote:
> >>
> >> Hello,
> >>
> >> Try the following
> >>
> >> cols <- sapply(tot, function(x) any(grepl("^E94", x)))
> >>
> >> To have the column numbers,
> >>
> >> which(cols)
> >>
> >>
> >> Hope this helps,
> >>
> >> Rui Barradas
> >>
> >> Às 19:50 de 05/10/19, Ana Marija escreveu:
> >>> Hello,
> >>>
> >>> I have a data frame tot which has many columns and many rows.
> >>>
> >>> I am trying to find all columns that have say a value in any of their
> >>> rows that STARTS WITH: "E94"
> >>>
> >>> for example there are columns like this:
> >>>
> >>>> unique(tot$diagnoses_icd9_f41271_0_44)
> >>> [1] NA      "E9420"
> >>>
> >>> I tried:
> >>> s=select(tot,starts_with("E94"))
> >>>
> >>> but this didn't return me anything. Data type in those columns is character.
> >>>
> >>> Thanks
> >>> Ana
> >>>
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