Programming Articles - Page 904 of 3363

To set the coefficient of one variable to 1 for logistic regression model, we can use offset function.For example, if we have a data frame called df that contains a binary column say y and three independent variables say x1, x2, and x3 and we want to create a logistic regression model with x1 coefficient equal to 1 then we can use the below given command −glm(y~x2+x3,offset=x1,data=df,family=binomial)Example 1Following snippet creates a sample data frame −y1

To display Y-axis labels with more decimal places, we would need to round the values of the vector or column for which we want to create the plot to the appropriate number of decimal places.After that axis function will be used for creating the graph. Before doing all this, the graph of original values should be created without axes.Check out the below example to understand how it works.ExampleFollowing snippet creates a sample data frame −x

To find the column name that has the least value for each row in an R data frame, we can use colnames function along with apply function.For Example, if we have a data frame called df then we can find column name that has the least value for each row by using the command mentioned below −df$Least_Column

To create pie chart using plotly, we first need to find the count data based on categories and then use the plot_ly function by mentioning chart type as "pie".To find the count data, we can use count function from dplyr package after that plot_ly function will be applied.Check out the below example to understand how it can be done.ExampleFollowing snippet creates the mtcars data −data(mtcars) head(mtcars, 20)OutputThe following mtcars data is created −                    mpg  cyl disp   hp  drat   wt    qsec   vs am gear carb Mazda RX4   ... Read More

To merge rows having same values in an R data frame, we can use the aggregate function.For example, if we have a data frame called df that contains two categorical columns say C1 and C2 and one numerical column Num then we can merge the rows of df by summing the values in Num for the combination of values in C1 and C2 by using the below given command −aggregate(Num~.,df,FUN=sum)Example 1Following snippet creates a sample data frame −grp1

To find the sum of a column values up to a particular value in another column, we can use cumsum function with sum function.For example, if we have a data frame called df that contains two columns say x and y and we want to find the sum of x values until y is equal to 2 then we can use the following command −sum(df$x[cumsum(df$y==2)==0])Example 1Following snippet creates a sample data frame −x1

To find the groupwise large and small values in an R data frame, we can use mutate function of dplyr package, the grouping can be easily done with the help of group_by function.For Example, if we have a data frame called df that contains grouping column say Grp and a numerical column Num then we can find the groupwise large and small values by using the below command −df%%group_by(Gp)%%mutate(Val=ifelse(Val==max(Val),"large","small"))Example 1Following snippet creates a sample data frame −Group

To create sample of rows using ID column, we can use sample function. We would need to apply the sample function on ID column and take the subset of rows with the help of single square brackets.For example, if we have a data frame called df that contains an ID column say ID then we can sample 4 rows of df using ID column as follows −df[sample(df$ID,4),]Example 1Following snippet creates a sample data frame −Emp_ID

To find the combination of matrix values in R, we can use expand.grid function with split function.For example, if we have a matrix called M then to create the combination of matrix values we can use the code mentioned below −do.call(expand.grid,split(M,rep(1:nrow(M),ncol(M))))Check out the examples given below to understand how it works.Example 1Following snippet creates a matrix −M1

To round values in proportion table in R, we can first save the proportion table in an object and then use the round function.For example, if we have a vector say X then we can create a proportion table for data in X using prop.table(table(X)) and store it in an object called Tab and then round the values to two decimal places by using the below given command −round(Tab,2)Example 1Following snippet creates a sample data frame −x1