Programming Articles - Page 898 of 3366

To find the column variance 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 column variance if some columns are categorical.ExampleCreate the data frameLet’s create a data frame as shown below −Group

To find the sum of rows of a column based on multiple columns in R data frame, we can follow the below steps −First of all, create a data frame.Then, use aggregate function to find the sum of rows of a column based on multiple columns.ExampleCreate the data frameLet’s create a data frame as shown below −Grp1

To subset groups that occur less than n times in R data frame, we can use filter function of dplyr package.For Example, if we have a data frame called df that contains a grouping column say Group then we can subset groups that occur less than 4 times by using the below mentioned command −df%%group_by(Group)%%filter(n()=4)Example 1Following snippet creates a sample data frame −Grp

To create bar plot of one column in an R data frame using ggplot2, we can use rownames of the data frame as x variable in aes.For Example, if we have a data frame called df that contains two columns say X and Y and we want to create the bar plot of values in Y then we can use the below mentioned command −ggplot(df,aes(rownames(df),Y))+geom_bar(stat="identity")ExampleFollowing snippet creates a sample data frame −x1

To display infinity and minus infinity symbol in one base R plot, we can use text function and expression function. Inside expression function we can put infinity word for the display of infinity and infinity word with minus sign for the display of minus infinity.Check out the below Examples to understand how it can be done.Example 1To display infinity and minus infinity symbol in one base R plot use the following code −plot(1:10, type="n") text(c(1, 5), expression(-infinity, infinity))OutputIf you execute the above given snippet, it generates the following Output −Example 2To display infinity and minus infinity symbol in one base ... Read More

To display infinity symbol in base R plot, we can use text function and expression function. Inside expression function we can put infinity word for the display of infinity. For Example, if we want to display infinity at position X=2 and Y=4 then we can use the below mentioned command −text(2, 4, expression(infinity))Example 1To display infinity symbol in base R plot, use the snippet given below −plot(1:10, type="n") text(5, 5, expression(infinity))OutputIf you execute the above given snippet, it generates the following Output −Example 2To display infinity symbol in base R plot, use the snippet given below −plot(1:10, type="n") text(5, 5, ... Read More

To subtract all values in a vector from all values in another vector in R, we can use sapply function with subtraction sign.For Example, if we have two vectors say X and Y and we want to subtract all values in Y from all values in X then we can use the command given below −sapply(X,"-",Y)Example 1Following snippet creates a sample data frame −x1

To find the sum of corresponding elements in all matrix’s stored in a list in R, we can use Reduce function with plus sign. For Example, if we have a list called LIST that contains multiple matrices and we want to find the sum of corresponding elements then we can use the command given below −Reduce("+",LIST)Check out the below Examples to understand how it works.Example 1To find the sum of corresponding elements in all matrix’s stored in a list in R, use the following snippet −List

To find the sum of all array elements in R, we can use Reduce function with plus sign. For Example, if we have an array called ARRAY and we want to find the sum of all values in this array then we can use the command Reduce("+",ARRAY).Check out the below Examples to understand how it works.Example 1To find the sum of all array elements in R use the snippet given below −Array1

To extract a data frame column values as a vector by matching a vector in R, we can use subsetting with %in% operator.For Example, if we have a data frame called df having a column say C and a vector V and we want to extract values in C if they match with V then we can use the command given below −df[df$C %in% V,"C"]Example 1Following snippet creates a sample data frame and vector −x1