Programming Articles - Page 1438 of 3363

Sometimes column values in an R data frame have single quote associated with them and to perform the analysis we need to remove that quote. Therefore, to remove single quote from string column, we can use gsub function by defining the single quote and replacing it with blank(not space) as shown in the below examples.Consider the below data frame −Example Live Demox1

To extract first value from a list, we first need to access the element using double square brackets then the sub-element of each element will be accessed using single square brackets. For example, if we have a list called LIST containing five elements each having 10 elements then the first sub-element of the LIST will be selected by using LIST[[1]][1].Example Live DemoList1

Generally, we put the plot title on top side of the plot but we can put it inside the plot as well. Of course, this will change the display of the chart but it will also get attraction of viewers. To do this, we can use the theme function of ggplot2 package where margin argument for plot title will change the position of the title.Consider the below data frame −Example Live Demox

To find the column index that matches a condition, we can use apply function. This condition could be values in columns greater than something, less than something, equal to something, or any other condition for numerical variables. For example, if we want to check which columns of data df contains value in rows greater than 5 then we can use the command apply(df,1, function(x) which(x>5)).Consider the below data frame −Example Live Demox1

When we sort a data frame column in R, the row names are lost but we might need them. Therefore, sorting without losing row names is required and it can be done with the help of order function. For example, if we have a data frame called df that has a column x then sorting of x without losing row names can be done by using the below command −df[order(df$x),,drop=FALSE]Consider the below data frame −Example Live Demox1

When we matrices of larger size and the data is expected to from the same distribution or from same sources then we might expect that the matrices are equal. In this type of situations, we would like to check whether the two matrices are equal or not. This can be done with the help of all.equal function as shown in the below examples.Example Live DemoM1

To display 0 at Y-axis, we can set the limits for Y-axis using scale_y_continuous function of ggplot2 package. For example, if we have two columns say x and y in an R data frame called df then the scatterplot with displaying 0 at Y-axis can be created by using the below commandggplot(df,aes(x,y))+geom_point()+scale_y_continuous(limits=c(0,”upperlimit”))Consider the below data frame −Example Live Demox

To create boxplot using ggplot2 without whiskers, we need to use coef argument inside geom_boxplot function. For example, if we have data frame called df and there exists one categorical variable x and one response variable y then the boxplots for categories without whiskers can be created by using ggplot(df,aes(x,y))+geom_boxplot(coef=0).Consider the below data frame −Example Live Demox

If we have two vectors say x and y, x contains 1, 6 and y contains 5,10 then the sequence of values between these two vectors will be 1, 2, 3, 4, 5 and 6, 7, 8, 9, 10. Here the sequence is created by using the corresponding elements in x and y. To do this in R, we can use mapply function as shown in the below examples.Example Live Demox1

The first quartile is the value that exists at the 25th percentile, that means there are 25% of values in the data that lie below first quartile. When we find the summary of data frame the output returns this value but if we want to extract only the first quartile then quantile function can be used by specifying the percentage using 0.25.Consider the below data frame −Example Live Demox