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Articles by Nizamuddin Siddiqui
Page 123 of 196
How to change the sign of even number rows in an R data frame column?
To change the sign of even number rows in an R data frame column, we can follow the below steps −First of all, create a data frame.Then, use vector multiplication with 1 and minus 1 to change the sign of even number rows.ExampleCreate the data frameLet’s create a data frame as shown below −x
Read MoreHow to multiply row values in a data frame having multiple rows with single row data frame in R?
To multiply row values in a data frame having multiple rows with single row data frame in R, we can follow the below steps −First of all, create a data frame with multiple rows and a data frame with single row.Then, use mapply function to multiply row values in the data frame having multiple rows with single row data frame.ExampleCreate the first data frameLet’s create a data frame as shown below −x
Read MoreHow to find the row standard deviation of columns having same name in data.table object in R?
To find the row standard deviation 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 sd function to find the row standard deviation 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 percentage of zeros in each column of a data frame in R?
To find the percentage of zeros in each column of a data frame in R, we can follow the below steps −First of all, create a data frame.Then, use colSums function along with nrow function to find the percentage of zeros in each column.Example 1Create the data frameLet’s create a data frame as shown below −x
Read MoreHow to multiply corresponding values from two data frames in R?
To multiply corresponding values from two data frames in R, we can follow the below steps −First of all, create two data frames.Then, use mapply function to multiply corresponding values from those two data frames.ExampleCreate the first data frameLet’s create a data frame as shown below −df1
Read MoreHow to create a column of first non-zero value in each row of an R data frame?
To create a column of first non-zero value in each row of an R data frame, we can follow the below steps −First of all, create a data frame with some zero values.Then, use apply function and a custom function to find the first non-zero in each row of the data frame.ExampleCreate the data frameLet’s create a data frame as shown below −x
Read MoreHow to unsplit a split data.table object in R?
To unsplit a split data.table object in R, we can follow the below steps −First of all, create a data.table object.Then, use split function to split the data.table object.After that, use do.call function along with rbind function unsplit the data frame.ExampleCreate the data.table objectLet’s create a data.table object as shown below −library(data.table) Grp
Read MoreCreate ggplot2 graph with reversed Y-axis and X-axis on top in R.
To create ggplot2 graph with reversed Y-axis and X-axis on top, we can use scale_y_reverse and scale_x_continuous function of ggplot2 package.For Example, if we have a data frame called df that contains two columns say X and Y and we want to create the scatterplot between X and Y with reversed Y-axis and X-axis on top then we can use the below command −ggplot(df,aes(X,Y))+geom_point()+scale_y_reverse()+scale_x_continuous(position="top")ExampleFollowing snippet creates a sample data frame −x
Read MoreHow to create correlation matrix plot without variables labels in R?
To create correlation matrix plot without variables labels in R, we can use tl.pos argument set to n.For Example, if we have a correlation matrix say M then we can create the correlation matrix plot without variables labels by using the below command −corrplot(M,tl.pos='n')ExampleFollowing snippet creates a sample data frame −x
Read MoreHow to create bar plot with gradient colors using ggplot2 in R?
To create bar plot with gradient colors using ggplot2, we can use scale_fill_gradient function where we can set the lower and higher color values.For Example, if we have a data frame called df that contains two columns say Cat and Count then we can create the bar plot with gradient colors by using the below command −ggplot(df,aes(Cat,Count,fill=Cat))+geom_bar(stat="identity")+scale_fill_gradient(low="blue",high="red")ExampleFollowing snippet creates a sample data frame −x
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