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Articles by Nizamuddin Siddiqui
Page 46 of 196
Find the column index of least value for each row of an R matrix
To find the column index of least value for each row in an R matrix, we can use apply function.For Example, if we have a matrix called M then we can find column that has the least value for each row by using the command as follows −apply(M,1,which.min)Example 1Consider the matrix given below −M1
Read MoreHow to convert days in a week to number in R data frame column?
To convert days in a week to number in R data frame column, we would need to convert the column into a factor by defining the weekdays as the levels and then read that column as integer.If we provide the correct sequence of weekdays during conversion then Monday will be converted to 1. Check out the below Examples to understand how it can be done.Example 1Following snippet creates a sample data frame −Week_Days
Read MoreHow to create transparent boxplot in R?
Be default, the boxplot created in base R or by using ggplot2 are not transparent in nature. If we want to create a transparent boxplot then we can use bwplot function from lattice package.For Example, if we have a vector called X then we can create transparent boxplot of X by using the below command −bwplot(x)Example 1To create transparent boxplot use the snippet given below −library(lattice) bwplot(rnorm(1000))OutputIf you execute the above given snippet, it generates the following Output −Example 2To create transparent boxplot add the following code to the above snippet −library(lattice) bwplot(rpois(1000, 5))OutputIf you execute all the above given ...
Read MoreFind the column name with the largest value for each row in an R data frame.
To find the column name that has the largest value for each row in an R data frame, we can use colnames function along with apply function.For Example, if we have a data frame called df then we can find column name that has the largest value for each row by using the command as follows −df$Largest_Column
Read MoreHow to find the quartile for each value in an R vector?
Any numerical data can be divided into four parts (four quarters) by using three quartiles, first quartile at 25%, second quartile at 50% and third quartile at 75% hence there will be four quarters to represent first 25%, second 25%, third 25% and the last 25% in a set of data.If we want to find the quartile (1 to 4) for each value in an R data frame column then we can use the quantile function and cut function as shown in the Examples given below.Example 1Following snippet creates a sample data frame −x
Read MoreHow to match and replace column names stored in R data frames in R-Programming?
If we have a data frame that contains a column of column names which matches with the column names of a data frame and another column that has different values then we can set these different values as the new column names of the data frame having matched column names.This can be done with the help of match function. Check out the below Examples to understand how it works.Example 1Following snippet creates a sample data frame −x1
Read MoreConvert a data frame with grouping column into a list based on groups in R.
To convert a data frame with grouping column into a list based on groups, we can use split function.For Example, if we have a data frame called df that contains a categorical column say Group and a numerical column say DV then we can convert df into a list based on groups in Group column by using the command as mentioned below −split(df$DV,df1$Group).Example 1Following snippet creates a sample data frame −Group
Read MoreDefine column and row names of a square matrix in a single line code if they are same in R.
If we have a square matrix or we want to create a square matrix and the row names and column names for this matrix are same then we can define these names in a single line of code.For Example, if we have a matrix called M that has 10 rows and 10 columns that has first ten alphabets as row and column names then we can define the column names as colnames(M)
Read MoreHow to subset non-duplicate values from an R data frame column?
Generally, the duplicate values are considered after first occurrence but the first occurrence of a value is also a duplicate of the remaining. Therefore, we might want to exclude that as well.The subsetting of non-duplicate values from an R data frame column can be easily done with the help of duplicated function with negation operator as shown in the below Examples.Example 1Following snippet creates a sample data frame −x
Read MoreCreate a data.table object of combination of correlation coefficients.
To create a data.table object of combination of correlation coefficients, we first need to find the correlation matrix then the combination of variables for which the correlation matrix is created then data.table will be used to combine the combination of variables and the correlation coefficients.Check out the below Examples to understand how it can be done.Example 1Following snippet creates a sample data frame −x1
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