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Articles by Nizamuddin Siddiqui
Page 7 of 196
How to create a column with column name for maximum value in each row of an R data frame?
To create a column with column name for maximum value in each row of an R data frame, we can follow the below steps −First of all, create a data frame.Then, use mutate function of dplyr package along with max.col function to create a column with column name for maximum value in each row of an R data frame.ExampleCreate the data frameLet’s create a data frame as shown below −x
Read MoreHow to find the row variance of columns having same name in data.table object in R?
To find the row variance of columns having same name in data.table object in R, we can follow the below steps −First of all, create a data.table object with some columns having same name.Then, use tapply along with colnames and var function to find the row variance of columns having same name.ExampleCreate the data.table objectLet’s create a data.table object as shown below −library(data.table) DT
Read MoreHow to find the row mean of columns having same name in R data frame?
To find the row mean of columns having same name in R data frame, we can follow the below steps −First of all, create a data frame with some columns having same name.Then, use tapply along with colnames and mean function to find the row mean of columns having same name.ExampleCreate the data frameLet’s create a data frame as shown below −df
Read MoreHow to find the sin of each value in columns if some columns are categorical in R data frame?
To find the sin 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 sin 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 remove hyphen at last position from every value in R data frame column?
To remove hyphen at last position from every value in R data frame column, we can follow the below steps −First of all, create a data frame with a column having hyphen at last position in every value.Then, use gsub function to remove hyphen at last position from every value in the column.ExampleCreate the data frameLet’s create a data frame as shown below −x
Read MoreHow to remove a particular value from a vector in R?
To remove a particular value from a vector, we can use negation of value.For example, if we have a vector called V that contains repetitive values starting from 1 to 10 and if we want to remove all 10s from V then we can use the command given below −V
Read MoreHow to find rows in an R data frame that do not have missing values?
Dealing with missing values is one of the most critical task in data analysis. If we have a large amount of data then it is better to remove the rows that contains missing values. For the removal of such rows we can use complete.cases function.For example, if we have a data frame called df that contains some missing values then we can remove the rows with missing values using the below given command −df[complete.cases(df),]Example 1Following snippet creates a sample data frame −x1
Read MoreHow to highlight a value with underline in base R plot?
To highlight a value with underline in base R plot, we can use underline function within text function. The text function will be used to define the value that we need to underline in the plot and underline function will only underline that part.Check out the below given example to understand how it works.ExampleTo highlight a value with underline in base R plot, use the code given below −plot(1:5)OutputIf you execute the above given code, it generates the following output −To highlight a value with underline in base R plot, add the following code to the above code −plot(1:5) text(4, ...
Read MoreHow to find the last non-missing value in each column of a data.table object?
To find the last non-missing value in each column of a data.table object, we can use lapply function along with tail function for NA values.For example, if we have a data.table object called DT then we can find the last non-missing value in each column of DT by using the below given command −DT[,lapply(.SD,function(x) tail(x[!is.na(x)],1))]Example 1Following snippet creates a data.table object −library(data.table) x1
Read MoreHow to convert a text vector into a matrix in R?
Sometimes numerical values are being read as strings and hence creating a matrix using that vector is not straight forward.For the conversion of text vector into a matrix, we need to use scan function and specify the appropriate number of rows or columns as shown in the below given examples.Example 1Consider the below given vector x1 −x1
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