[Solved] Calculate the mean of one column from several CSV files

[ad_1] You do not need more functions. The solution can be simpler from my understanding in 6 lines: pollutantmean <- function(directory, pollutant, id = 1:10) { filenames <- sprintf(“%03d.csv”, id) filenames <- paste(directory, filenames, sep=”https://stackoverflow.com/”) ldf <- lapply(filenames, read.csv) df=ldply(ldf) # df is your list of data.frames mean(df[, pollutant], na.rm = TRUE) } 2 [ad_2] … Read more

[Solved] How can I create a new column for month and year from datetime and logically compare date time in R [closed]

[ad_1] You could do this: df <- data.frame(date=c(“18MAY2013:00:00:00″,”19MAY2013:00:00:00″)) df$year <- format(as.Date(df$date,”%d%B%Y”),”%Y”) df$month <- format(as.Date(df$date,”%d%B%Y”),”%m”) date year month 1 18MAY2013:00:00:00 2013 05 2 19MAY2013:00:00:00 2013 05 1 [ad_2] solved How can I create a new column for month and year from datetime and logically compare date time in R [closed]

[Solved] How can I estimate standard error in maximum likelihood destinati in [closed]

[ad_1] You have to evaluate the Hessian to estimate standard error for a parameter fit = optim(start.theta, fn = function, #start.theta initial value of paramter hessian = TRUE, method = “L-BFGS-B”, #hessian True to calculate Hessian matrix lower = c(), upper = c(), control = list(trace = 1, fnscale = -1)) #fnscale= -1 to maximize … Read more

[Solved] Matching and replacement with gsub [closed]

[ad_1] We can try sub sub(“(V).*(neck)”, “\\1 \\2”, words_1) #[1] “V neck” “V neck” “V neck” Or a general approach would be sub(“([A-Z]+)[^A-Za-z]*([a-z]+)”, “\\1 \\2”, words_1) 2 [ad_2] solved Matching and replacement with gsub [closed]

[Solved] Grouping by a column in R [closed]

[ad_1] We can try data.table. Convert the ‘data.frame’ to ‘data.table’ (setDT(df2), grouped by ‘RouteId’, if any of the run-length-type id of the logical vector (StopType==’Load’) is greater than 2, we get the Subset of Data.table (.SD). This will give the rows with ‘RouteId’ 103. library(data.table) setDT(df2)[,if(any(rleid(StopType==’Load’) >2)) .SD ,.(RouteId)] # RouteId StopOrder StopType #1: 103 … Read more

[Solved] Converting R code to Markdown or RNotebok

[ad_1] Within R studio, you can choose R markdown . Navigate to File Option -> New File -> R Markdown There are no changes in coding. All codes that you write in R would be as-is. Just with a flexibility that you can add comments and explain your code. Make sure in .Rmd file, there … Read more

[Solved] Sum values in matrix with if statement

[ad_1] The second column is binary. So one way would be to change it to logical vector, subset the values that correspond to ‘ON’ and ‘OFF’ (i.e. 1 and 0), get the difference of the sum of both and multiply with 40. 40*(sum(ccmix[,1][!!ccmix[,2]]) – sum(ccmix[,1][!ccmix[,2]])) The negate function (!) converts 0 to TRUE and 1 … Read more

[Solved] Understanding kmeans clustering in r [closed]

[ad_1] 1. What does the cluster sizes mean? You provided 16 records and told kmeans to find 3 clusters. It clustered those 16 records into 3 groups of A: 3 records, B: 10 records and C: 3 records. 2. What are the cluster means? These numbers signify the location in N-Dimensional space of the centroid … Read more