It all makes so much sense now On Thu, Apr 7, 2016 at 10:04 AM, Jeff Newmiller <jdnew...@dcn.davis.ca.us> wrote:
> lapply(colordata2[ -1 ], f ) > > When you put the parentheses on, you are calling the function yourself > before lapply gets a chance. The error pops up because you are giving a > vector of numbers (the answer f gave you) to the second argument of lapply > instead of a function. > -- > Sent from my phone. Please excuse my brevity. > > On April 7, 2016 7:31:18 AM PDT, Michael Artz <michaelea...@gmail.com> > wrote: >> >> If you are not using an anonymous function and say you had written the >> function out >> >> The below gives me the error > 'f(colordata2$color1)' is not a function, >> character or symbol' But then how is the anonymous function working? >> >> >> f <- function(col){ >> ifelse(col == 'blue', 1, 0) >> } >> responses <- lapply(colordata2[ -1 ], f(colordata2$color1) ) >> >> 'f(colordata2$color1)' is not a function, character or symbol' >> >> then how could you then use this fuction in lapply if not for the >> anonymous function? >> >> On Thu, Apr 7, 2016 at 8:17 AM, Jeff Newmiller <jdnew...@dcn.davis.ca.us> >> wrote: >> >>> Lapply is not a vectorized function. It is compact to read, but it would >>> not be worth using for this calculation. >>> >>> However, if your data frame had multiple color columns in your data >>> frame that you wanted to make responses for then you might want to use >>> lapply as a more compact version of a for loop to repeat this operation. >>> >>> colordata2 <- data.frame(id = c(1,2,3,4,5), color1 = c("blue", "red", >>> "green", "blue", "orange"), color2 = c("orange", "green", >>> "blue", "red", "red")) >>> responses <- lapply( colordata2[ -1 ], function(col) { ifelse(col == >>> 'blue', 1, 0) } ) >>> names(responses) <- names( colordata2 )[-1] >>> >>> where each of the columns other than the first is handed in turn to the >>> anonymous function that does the response calculation. The result is a data >>> frame (list of columns) with no column names, so I give the new columns >>> names based on the old column names. You could choose different names, e.g. >>> >>> names(responses) <- paste0( "response", 1:2 ) >>> >>> but you have to be careful to fix that code whenever you change the >>> colordata2 data frame to have more columns. >>> -- >>> Sent from my phone. Please excuse my brevity. >>> >>> On April 7, 2016 4:57:04 AM PDT, Michael Artz <michaelea...@gmail.com> >>> wrote: >>>> >>>> Thaks so much! And how would you incorporate lapply() here? >>>> >>>> On Thu, Apr 7, 2016 at 6:52 AM, David Barron <dnbar...@gmail.com> wrote: >>>> >>>> ifelse is vectorised, so just use that without the loop. >>>>> >>>>> colordata$response <- ifelse(colordata$color == 'blue', 1, 0) >>>>> >>>>> David >>>>> >>>>> On 7 April 2016 at 12:41, Michael Artz <michaelea...@gmail.com> wrote: >>>>> >>>>> Hi I'm not sure how to ask this, but its a very easy question to answer >>>>>> for >>>>>> an R person. >>>>>> >>>>>> What is an easy way to check for a column value and >>>>>> then assigne a new >>>>>> column a value based on that old column value? >>>>>> >>>>>> For example, Im doing >>>>>> colordata <- data.frame(id = c(1,2,3,4,5), >>>>>> color = c("blue", "red", >>>>>> "green", "blue", "orange")) >>>>>> for (i in 1:nrow(colordata)){ >>>>>> colordata$response[i] <- ifelse(colordata[i,"color"] == "blue", 1, 0) >>>>>> } >>>>>> >>>>>> which works, but I don't want to use the for loop I want to "vecotrize" >>>>>> this. How would this be implemented? >>>>>> >>>>>> [[alternative HTML version deleted]] >>>>>> >>>>>> ------------------------------ >>>>>> >>>>>> R-help@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. >>>>> >>>>> >>>>> >>>> >>>> [[alternative HTML version deleted]] >>>> >>>> ------------------------------ >>>> >>>> R-help@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. >>>> >>>> >> [[alternative HTML version deleted]] ______________________________________________ R-help@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.