Selecting by position is not generally recommended, but rename () ing by position can be very useful, particularly if the variable names are very long, non-syntactic, or duplicated. When you merge datasets by rows is important that datasets have exactly the same variable names and the same number of variables. There are now five ways to select variables in select () and rename (): By position: df > select (1, 5, 10) or df > select (1:4). Or we can merge datasets by adding columns when we know that both datasets are correctly ordered: Using the code below we are adding new columns:įinaldt <- merge(dataset1, dataset2, by="id") Merge dataset1 and dataset2 by variable id which is same in both datasets. However, for the function cbind is necessary that both datasets to be in same order. In case that datasets doesn't have a common variable use the function cbind. To add columns use the function merge() which requires that datasets you will merge to have a common variable. You can merge columns, by adding new variables or you can merge rows, by adding observations. If datasets are in different locations, first you need to import in R as we explained previously. ![]() Merging datasets means to combine different datasets into one. Here is an example how to recode variable patients:ĭf$patients <- ifelse(df$patients=150, 100, ifelse(df$patients=350, 300, NA))įor recoding variable I used the function ifelse(), but you can use other functions as well. Or we can also delete the variable by using command NULL: Using dataset above we rename the variable: Now we are interested to rename and recode a variable in R. Now we will create a new variable called totcosts as showing below: Usually the operator * for multiplying, + for addition, - for subtraction, and / for division are used to create new variables.ĭf <- ame(hospital, patients, costs) Variables are always added horizontally in a data frame. The common function to use is newvariable <- oldvariable. To create a new variable or to transform an old variable into a new one, usually, is a simple task in R.
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