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Server Side Programming Articles
Page 140 of 2107
How to display 0 at Y-axis using ggplot2 in R?
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 −Examplex
Read MoreHow to change the order of elements in a list in R?
A list in R can contain many types of elements such as vector, data frame, matrices, etc. Sometimes the order of these elements matter, especially in situations when we have large size elements because it is difficult to view large size elements of a list. This ordering can be done with the help of single square bracket and combine operator c as shown in the below examples.ExampleList1
Read MoreHow to perform Wilcoxon test for all columns in an R data frame?
Performing Wilcoxon test for all columns in an R data frame means that we want to use this test for single samples and the Wilcoxon test for single sample is used to test for the median of the sample, whether the median is equal to something or not. And if we do not provide any value then zero is the reference value. To perform Wilcoxon test for all columns can be done with the help of apply function and wilcox.test as shown in the below example.Consider the below data frame −Examplex1
Read MoreWhat is the difference between na.omit and na.rm in R?
The na.omit performs any calculation by considering the NA values but do not include them in the calculation, on the other hand, na.rm remove the NA values and then perform any calculation. For example, if a vector has one NA and 5 values in total then their sum using na.omit will be calculated by excluding NA and by using na.rm it will be calculated by removing NA.Consider the below data frame −Examplex1
Read MoreHow to find the column index in an R data frame that matches a condition?
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 −Examplex1
Read MoreHow to create a sequence of values between two vectors in R using corresponding elements?
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.Examplex1
Read MoreHow to check if two matrices are equal in R?
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.ExampleM1
Read MoreHow to sort an R data frame column without losing row names?
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 −Examplex1
Read MoreHow to display a line in segment of a plot using ggplot2 in R?
To display a line in segment of a plot, we can use geom_segment function of ggplot2 package where we need to pass the initial and the ending values for both the axes. For example, if we have data frame called df that contains x and y then a scatterplot with a line segment can be created by using the below command −ggplot(df,aes(x,y))+geom_point()+ geom_segment(aes(x=xstart,xend=xlast,y=ystart,yend=ylast))Consider the below data frame −Examplex
Read MoreHow to extract first value from a list in R?
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].ExampleList1
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