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

[Rui Barradas]

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
>>>
>>> ______________________________________________
>>> R-help using r-project.org mailing list -- To UNSUBSCRIBE and more, see
>>> 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.
>>>