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Articles by Nizamuddin Siddiqui
Page 162 of 196
How to save a plot as SVG created with ggplot2 in R?
There are multiple ways to save a plot created in R. Base R provides, metafile, bitmap, and postscript options to copy and save the plots created in R but we can also save the plots created with ggplot2 as an SVG file with the help of svglite package. The ggsave function of svglite package does this job easily and we can also define the height and width of the plot inside this function.Example Live DemoInstall the svglite package −install.packages("svglite")Consider the ToothGrowth data and create a scatterplot between len and dose −head(ToothGrowth) len supp dose 1 4.2 VC ...
Read MoreWhy do we get warning 'newdata' had 1 row but variables found have X rows while predicting a linear model in R?
The reason we get newdata had 1 row warning is the newdata is not correctly defined. We should give the name of the explanatory variable or independent variable to the newdata so that the model can identify that we are passing the mean of the explanatory variable, otherwise it considers all the values of the explanatory hence the result of the predict function yields the predicted values for the sample size.Example Live DemoConsider the below data frame −set.seed(123) x
Read MoreHow to replace space in a string value for some elements in a column of an R data frame?
Most of the times, the string data is in bad shape and we need to make it appropriate so that we can easily proceed with the analysis. There is also a situation in which a string column has some values where an extra space is used which was not required, therefore, it does not match with the rest of the column values. To remove these spaces, we can use lapply and gsub function.ExampleConsider the below data frame −x1
Read MoreHow to change the column names in R within aggregate function?
The column names in an R data frame are an important part of the data because by reading the column names any viewer is likely to understand the theoretical background behind it. If that name is not appropriate then we might want to change it. While using the aggregate function to calculate mean or any other statistical summary, it is possible to change that name with another name by defining the new name with list.ExampleConsider the below data frame −set.seed(1) x1
Read MoreHow to find the row and column number for the minimum and maximum values in an R matrix?
A matrix can have one or more than one minimum and maximum values. Also, the size of the matrix can be just one column and multiple rows or thousands of columns and thousands of rows. The row number and column number for the minimum and maximum values in a matrix can be found by using the following syntax −For Maximumwhich(“Matrix_Name”==min(“Matrix_Name”),arr.ind=TRUE)For Minimum>which(“Matrix_Name”==max(“Matrix_Name”),arr.ind=TRUE)Example M1
Read MoreHow to find pairwise maximum among multiple vectors in R?
The pairwise maximum refer to the values that are largest between the vectors. For example, if we have a vector that contains 1, 2, 3 and a second vector contains 2, 1, 4 then the pairwise maximum will be 2, 2, 4 because the maximum between 1 and 2 is 2, the maximum between 2 and 1 is 2, and the maximum between 3 and 4 is 4. In R, we can find these maximum values for many vectors using pmax function.Example> x1 y1 pmax(x1, y1) [1] 27 28 65 25 17 21 29 > x2 x2 [1] 7 ...
Read MoreHow to repeat a simulation to a fixed number of times in R?
Often, we simulate random values from different distributions in R. The base R provides some inbuilt functions for the same and if we want to repeat the simulation a fixed number of times then we write these inbuilt functions again and again. But we can do multiple simulations using a single line of code with the help of replicate function, that means if we want to simulate ten uniform random variables ten times then it can be done by using replicate function.Examplesreplicate(10, runif(5, 2, 5)) [, 1] [, 2] [, 3] [, 4] [, 5] [, 6] [, 7] [, ...
Read MoreHow to create a column in an R data frame with cumulative sum?
The cumulative sum is used to determine the total sum of a variable or group and helps us to understand the changes in the values of that variable or group over time. While creating the cumulative, we must be sure that the total sum and the cumulative sum of the last value (depending on the direction of sum) are same. We can use mutate function of dplyr package to find the cumulative and create a column for it.ExampleConsider the below data frame −x1
Read MoreHow to create a rank variable using mutate function of dplyr package in R?
A rank variable is created to convert a numerical variable into ordinal variable. This is useful for non-parametric analysis because if the distribution of the numerical variable is not normal or there are assumptions of parametric analysis that cannot be followed by the numerical variable then the raw variable values are not analyzed directly. To create a rank variable using mutate function, we can use dense_rank argument.ExampleConsider the below data frame −set.seed(7) x1
Read MoreHow to create boxplot with horizontal lines on the minimum and maximum in R?
A boxplot shows the minimum, first quartile, median, third quartile, and maximum. When we create a boxplot with ggplot2 it shows the boxplot without horizontal lines on the minimum and maximum, if we want to create the horizontal lines we can use stat_boxplot(geom= 'errorbar') with ggplot function of ggplot2.ExampleConsider the below data frame −set.seed(101) Gender
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