To find the sum of a column values up to a particular value in another column, we can use cumsum function with sum function.For example, if we have a data frame called df that contains two columns say x and y and we want to find the sum of x ... Read More

To create sample of rows using ID column, we can use sample function. We would need to apply the sample function on ID column and take the subset of rows with the help of single square brackets.For example, if we have a data frame called df that contains an ID ... Read More

Any numerical data can be divided into four parts by using three quartiles, first quartile at 25%, second quartile at 50% and third quartile at 75% hence there will be four quarters to represent first 25%, second 25%, third 25% and the last 25% in a set of data.If we ... Read More

To find the combination of matrix values in R, we can use expand.grid function with split function.For example, if we have a matrix called M then to create the combination of matrix values we can use the code mentioned below −do.call(expand.grid, split(M, rep(1:nrow(M), ncol(M))))Check out the examples given below to ... Read More

To round values in proportion table in R, we can first save the proportion table in an object and then use the round function.For example, if we have a vector say X then we can create a proportion table for data in X using prop.table(table(X)) and store it in an ... Read More

A list may contain vectors, data frames, matrices, lists etc. If a list contains matrices and we want to convert those matrices into data frames then lapply function can be used along with as.data.frame function.For example, if we have a list called LIST that contains matrices then we can convert ... Read More

To find the mean of a column grouped by date, we can simply use aggregate function. For Example, if we have a data frame called df that contains a date column say Date and numerical column say Num then we can find the mean of Num by dates in the ... Read More

To rotate a ggplot2 graph, we can save it in an object and then use the print function by defining the angle with viewport.For example, if we have a graph saved in an object called PLOT then we can rotate it to 180 degrees by using the below mentioned command ... Read More

To find the conditional frequency for all columns based on a condition, we can use for loop where we will define the length of each column with condition for which we want to find the frequency.For example, if we have a data frame called df and we want to find ... Read More

To add row percentage to contingency table in R, we can use rowSums and sum function with table values and combine them with cbind function.For Example, if we have a table called TAB then we can add row percentages to TAB by using the below command −cbind(TAB, rowSums(TAB), rowSums(TAB)/sum(TAB))Example 1Following ... Read More