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To find the frequency of particular value in rows of an R data frame, we can use mutate function of dplyr package along with rowSums function.For example, if we have a data frame called df then we can find the number of 5’s in each row of df by using the below command −df%>%mutate(Number_of_Fives=rowSums(.==1))Example 1Following snippet creates a sample data frame −x1
To find the column maximum if some columns are categorical in R data frame, we can follow the below steps −First of all, create a data frame.Then, use numcolwise function from plyr package to find the column maximum if some columns are categorical.Example 1Create the data frameLet’s create a data frame as shown below −Group
To replace numbers written in words with numbers in an R data frame column, we can use within function.For example, if we have a data frame called df that contains a column say X having numbers from 1 to 5 written in words then we can convert them into numbers by using the below command −within(df,X
A dichotomous column can be represented by words such as Yes/No, Good/Bad, Right/Wrong etc. To replace such words with number, say 1 and 0 we can use ifelse function.For example, if we have a data frame called df that contains a column Binary with Yes and No values then we can replace Yes with 1 and No with 0 by using the below command −df$Binary
To select data frame columns based on their class in R, we can follow the below steps −First of all, create a data frame or consider an inbuilt data set.Then, use select_if function of dplyr package with class function.Example 1str(CO2)OutputOn executing, the above script generates the below output(this output will vary on your system due to randomization) −Classes ‘nfnGroupedData’, ‘nfGroupedData’, ‘groupedData’ and 'data.frame':84 obs. of 5 variables: $ Plant : Ord.factor w/ 12 levels "Qn1"
To create a histogram for uniform data in R, we can simply use hist function but the bars size may vary even if the frequency is same. Therefore, for this purpose, we need to define the breaks as shown in the below example.ExampleTo create a histogram for uniform data in R, use the code given below −hist(1:6)OutputIf you execute the above given code, it generates the following output −To create a histogram for uniform data in R, use the code given below −hist(1:8) OutputIf you execute the above given code, it generates the following output −To create a histogram for ... Read More
To find the smallest number in an R data frame column excluding values zero or less, we can use min function along with subsetting of values greater than 0 through single square brackets.For example, if we have a data frame called df that contains a column say X then the smallest number excluding values zero or less can be found by using the below command −min(df[df$X>0,1])Example 1Following snippet creates a sample data frame −x
To find the dot product of two matrices in R, we can use dot function of geometry package.For Example, if we have two matrices say matrix1 and matrix2 then we can use the dot product of these two matrices by using the below given command −dot(matrix1,matrix2)Example 1Following snippet creates a sample matrix −M1
The empirical distribution can be found by using the function ecdf and if we want to create a plot of empirical distribution then plot function will be used.For example, if we have a vector called X then plot of empirical distribution can be created by using the below command −plot(ecdf(X))Example 1To create a plot of empirical distribution in R, use the code given below −x
To create sequential index value for binary column assigning 0 to FALSE values in data.table object in R, we can follow the below steps: −First of all, create a data.table object with binary column.Then, use rle function along with sequence and lengths function to create sequential index column.ExampleCreate the data.table objectLet’s create a data.table object as shown below −library(data.table) x