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Articles by Nizamuddin Siddiqui
Page 156 of 196
How to create confusion matrix for a rpart model in R?
To create confusion matrix for a rpart model, we first need to find the predicted values then the table of predicted values and the response variable in the original data can be created, which will be the confusion matrix for the model.For Example, if we have a vector of predicted values say P and original values in data frame df$O then the confusion matrix can be created by using the following command −table(P, df$O)Check out the below Examples to understand how it can be done.Example 1Following snippet creates a sample data frame −Dep_Var1
Read MoreFind the product of vector elements in pairs moving forward in R.
To find the product of vector elements in pairs moving forward, we can use prod function along with combn function.For Example, if we have a vector called V and we want to find the product of elements of V in pairs moving forward then we can use the following command −combn(V,2,prod)Example 1Following snippet creates a sample data frame −x1
Read MoreHow to create bar plot using ggplot2 with structure data frame?
To create bar plot using ggplot2 with structure data, we need to set the stat argument of geom_bar function to identity. This is same for the regular data frame.For example, if we have a structured data frame called df that contains a column X for categories and a numerical column say Y for frequency then we can the bar plot for this data by using the below given command −ggplot(df,aes(X,Y))+geom_bar(stat="identity")ExampleFollowing snippet creates a sample data frame −df
Read MoreHow to display data frame name in ggplot2 graph title in R?
To display data frame name in ggplot2 graph title, we can use ggtitle function and pass the name of the data frame.For example, if we have a data frame called df that contains two columns say x and y and we can create a point chart between x and y then the plot with data frame name as title can be created by using the below mentioned command −ggplot(df,aes(x,y))+geom_point()+ggtitle("df")ExampleFollowing snippet creates a sample data frame −x
Read MoreHow to create a colored frame for ggplot2 graph in R?
To create a colored frame for ggplot2 graph, we can use theme function and set the plot.background argument to different color for rectangular element.For example, if we have a data frame called df that contains two columns say X and Y then we can create point chart between X and Y with blue colored frame of the plot using the below mentioned command −ggplot(df,aes(X,Y))+geom_point()+theme(plot.background=element_rect(colour="blue",size=3))ExampleFollowing snippet creates a sample data frame −x
Read MoreHow to add title to regression model using stargazer in R?
To add title to regression model using stargazer, we can use title argument inside stargazer function.For example, if we have a model called Reg_Model with Output as text then the title to this model using stargazer can be added by using the below mentioned command −stargazer(Reg_Model,type="text",title="Regression Model between x and y")Example 1Following snippet creates a sample data frame −x
Read MoreHow to delete a row from an R data frame if any value in the row is greater than n?
To delete a row from an R data frame if any value in the row is greater than n can be done by using the subsetting with single square brackets and negation operator. We will subset the values that are greater than n and then take the negation of the subset as shown in the below given examples.Example 1Following snippet creates a sample data frame −x1
Read MoreHow to find the sum product of two matrix by row in R?
To find the sum product of two matrix by row in R, we can use rowSums function by passing the multiplication of the matrices.For example, if we have two matrices say Matrix1 and Matrix2 then, the sum product of these two matrices by row can be found by using the following command −rowSums(Matrix1*Matrix2)Example 1Following snippet creates a matrix −M1
Read MoreHow to multiply each value in a column by a constant in R?
To multiply each value in a column by a constant, we can use multiplication sign *.For example, if we have a data frame called df that contains a column say x. Now, if we want to multiply each value in x with 10 then we can use the below mentioned command −df$x
Read MoreHow to deal with error invalid xlim value in base R plot?
The error invalid xlim value occurs when we incorrectly provide the xlim values, these values are not used in sequence, we just need to provide first and the last value. For Example, if we want to create a point chart of 1 to 5 with xlim having values between -5 to 15 then we can use the command as follows −plot(1:5, xlim=c(-5:15))ExampleAdd the following code to the above command −plot(1:10) OutputIf you execute the above given command, it generates the following Output −Add the following code to the above snippet −plot(1:10) plot(1:10, xlim=c(-15:15)) Error in plot.window(...) : invalid 'xlim' value ...
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