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Articles by Nizamuddin Siddiqui
Page 140 of 196
Find the column name that contains value greater than a desired value in each row of an R data frame.
To find the column name that contains value greater than a desired value in each row of an R data frame, we can use apply function along with lapply function.For Example, if we have a data frame called df and we want to extract column names for each row having values greater than 5 then we can use the command given below −lapply(apply(df,1, function(x) which(x5)),names)Example 1Following snippet creates a sample data frame −x1
Read MoreHow to extract the last value of all elements of a list in R?
To extract the last value of all elements of a list in R, we can follow the below stepss −First of all, create a list.Then, use tail function with sapply function to extract the last value of all elements in the list.Example 1Create the listLet’s create a list as shown below −List
Read MoreHow to repeat a whole data.table object in R?
To repeat a whole data.table object in R, we can follow the below steps −First of all, create a data.table object.Then, use rep function to repeat the data.table object.ExampleCreate the data.table objectLet’s create a data.table object as shown below −library(data.table) x
Read MoreHow to find the position of maximum of each numerical column if some columns are categorical in R data frame?
To find the position of maximum of each numerical column 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 maximum of each numerical column if some columns are categorical.Example 1Create the data frameLet’s create a data frame as shown below −Level
Read MoreHow to find the cosine of each value in columns if some columns are categorical in R data frame?
To find the cosine of each value in columns 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 cosine of each value in columns if some columns are categorical.ExampleCreate the data frameLet’s create a data frame as shown below −Level
Read MoreHow to create a binary random variable in R with given probability?
To create a binary random variable in R with given probability, we can use the rbinom function with sample size argument n, success size argument size, and probability argument prob. To understand, how it can be done check out the below examples.Example 1Create the vector using rbinom function with n = 500, size = 1, and prob = 0.05 as shown below −x1
Read MoreHow to find the column median if some columns are categorical in R data frame?
To find the column median 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 median if some columns are categorical.Example 1Create the data frameLet’s create a data frame as shown below −Group
Read MoreConvert a single column matrix into a diagonal matrix in R.
A diagonal matrix is a type of square matrix that contains zero at non-diagonal elements starting from left-upper to right-bottom.To convert a single column matrix into a diagonal matrix in R, we can use diag function along with matrix function and use ncol argument where we can put the number of columns equal to the number of values in the single column matrix.Check out the Examples given below to understand how it can be done.Example 1Following snippet creates a sample matrix −M1
Read MoreHow to create a replacement column with multiple conditions and NA in R data frame?
To create a replacement column with multiple conditions and NA in R data frame, we can follow the below steps −First of all, create a data frame.Then, use nested ifelse function to create a replacement column with multiple conditions.ExampleCreate the data frameLet’s create a data frame as shown below −x
Read MoreHow to convert a vector into a diagonal matrix in R?
A diagonal matrix is a type of square matrix that contains zero at non-diagonal elements starting from left-upper to right-bottom. To convert a vector into a diagonal matrix in R, we can use diag function along with matrix function and use ncol argument where we can put the number of columns equal to the number of values in the vector. Check out the Examples given below to understand how it can be done.Example 1Following snippet a sample list −V1
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