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Articles by Nizamuddin Siddiqui
Page 55 of 196
How to find the fractional power of a negative number in R?
To find the fractional power of a negative number, we can find the power separately for the numerator and denominator where denominator will have the numerator 1. For example, if we have a vector called x that contains a single value -10 then the fractional power 15/7 of x can be found by using the command ((x)^15)^(1/7)Examplex1
Read MoreHow to create boxplot in base R with higher width of the box lines?
To create boxplot in base R with higher width of the box lines, we can use the boxlwd argument inside boxplot function. For example, if we have a vector called x then we can create the boxplot with higher width of the box lines using the command −boxplot(x,boxlwd=5)Examplex
Read MoreHow to replace a particular value in R data frame with a new value?
To replace a particular value in R data frame with a new value, we can use ifelse function where the new value will be placed after the condition and if the column values do not match the condition then the same column will be placed. For example, if we have a data frame called df that contains a column x having 20 values and some of them are 5 and if we want to replace 5 with 2 then we can use the command df$x
Read MoreHow to test for significant relationship between two categorical columns of an R data frame?
To test for the significance of proportion between two categorical columns of an R data frame, we first need to find the contingency table using those columns and then apply the chi square test for independence using chisq.test. For example, if we have a data frame called df that contains two categorical columns say C1 and C2 then the test for significant relationship can be done by using the command chisq.test(table(df$C1,df$C2))Examplex1
Read MoreHow to add approximately equal sign in a plot using ggplot2 in R?
To add approximately equal sign in a plot using ggplot2, we can use tilde sign twice as ~~ in geom_text function of ggplot2 package. For example, we can do this by using the following syntax geom_text(aes(label="NULL%~~%")). Check out the below example to understand how it works.ExampleConsider the below data frame −x
Read MoreHow to create a list of regression models for predefined vectors in R?
To create a list of regression models for predefined vectors, we can create a blank list and then use the for loop to create the list of regression models. For example, if we have two vectors say x and y, and we want to create a list of regression model between x and y then we create a blank list using list() and perform for loop a particular number of times as shown in the below examples.Example1x
Read MoreHow to change the point size in geom_point conditionally in R?
To change the point size in geom_point conditionally, we can define the condition in geom_point with aes and the size using scale_size_manual function of ggplot2 package. For example, if we have a data frame called df that contains two columns say x and y then the scatterplot with different size of points for x values greater than 5 and less than equal to 5 can be drawn by using the below command −ggplot(df, aes(x, y))+geom_point(aes(size=x>5))+scale_size_manual(values=c(4, 7))ExampleConsider the below data frame −x6))+scale_size_manual(values=c(4, 7)) Output
Read MoreHow to find the proportion of each value for a cross tab obtained from a data frame in R?
To find the proportion of each value for a cross tab obtained from a data frame, we can use prop.table function. Suppose we have a data frame called df that contains three columns, two categorical say C1 and C2 and one numerical say Y then the cross tab will be created by using the command xtabs(Y~.,df). Now the proportion of each value can be found by using prop.table(xtabs(Y~.,df),1).Example1Consider the below data frame −f1
Read MoreHow to change default point size of geom_point in R?
To change the default point size of geom_point, we need to use update_geom_defaults function. Specifically, for the change of point size the syntax will be as follows −update_geom_defaults("point",list(size=”value”))Here, we can change the value according to our need.ExampleConsider the below data frame −x
Read MoreHow to create data frame using nested list elements in R?
To create data frame using nested list elements, we would need to unlist the list elements and store them in a matrix then read as a data frame using data.frame function. For example, if we have a nested called LIST then the data frame can be created by using the command −data.frame(matrix(unlist(LIST),ncol=”No of columns we want”,byrow=F))Check out the below example to understand how it works.ExamplenestedList
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