R: Using ifelse to change a value according to a value in a different column

Question

I have a list of patients and the hospitals where they are treated. However one of the hospitals is listed as being in another state so I wanna change it

I'm trying to do it like this:

db <- ifelse(db$hospital=="NYC Hospital", db$State=="New York"),)

However it says I'm missing the NO argument. How can I get around this?

A couple of things wrong here. (1) You are replacing the whole `data.frame` object (inferring) with a vector. This is not incorrect syntax, but seems suspect. (2) The error cannot be more clear: the `no=` argument to the `ifelse` function is **required**, and you are not providing it. The `ifelse` function, if it "spoke", says *"when the `test=` is true then return `yes=`, otherwise return `no=`"* (for each condition in the `test=` vector, which should be the same length as `yes=`/`no=`). — r2evans, Jul 29 '20 at 20:14
Please provide sample data with `dput(x)` where `x` is a *small* sample of your `db` variable that includes that hospital (positive test) and other hospitals (negative test). Refs: https://stackoverflow.com/q/5963269, [mcve], and https://stackoverflow.com/tags/r/info. — r2evans, Jul 29 '20 at 20:15

score 0 · Accepted Answer · answered Jul 29 '20 at 20:07

0

Just leave it the same when the answer is NO:

db$State <- ifelse(db$hospital == "NYC Hospital", "New York", db$State)

Next time try using the code syntax

answered Jul 29 '20 at 20:07

Fernando

116
8

When I do this, it changes the names of all the states into numbers, and sets New York as state "0" – mabj4815 Jul 29 '20 at 20:12
1

A great example of why you need to provide sample data. It's likely you have `factor`s in your data. – r2evans Jul 29 '20 at 20:13
if you don't mind changing between `factor` and `character` then you can use this at the begining to avoid the problem: `db$State – Fernando Jul 29 '20 at 20:18
Changed it from factor to character and it works now. thanks! – mabj4815 Jul 29 '20 at 20:20

R: Using ifelse to change a value according to a value in a different column

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