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Articles by Nizamuddin Siddiqui
Page 101 of 196
How to create blue or red colored boxplots in R using ggplot2?
The default color of boxplot area in R using ggplot2 is white but we might want to change that color to something more attracting, for example blue or red. To do this purpose, we can use geom_boxplot function of ggplot2 package with fill argument by passing the color names.Consider the below data frame −Exampleset.seed(1321) v1
Read MoreHow to find the root mean square of a vector in R?
To find the root mean square of a vector we can find the mean of the squared values then take the square root of the resulting vector. This can be done in a single and very short line of code. For example, if we have a vector x and we want to find the root mean square of this vector then it can be done as sqrt(mean(x^2)).Examplex1
Read MoreHow to round correlation values in the correlation matrix to zero decimal places in R?
To find the correlation matrix, we simply need to use cor function with the data frame object name. For example, if we have a data frame named as df then the correlation matrix can be found by using cor(df). But the result will have too many decimal places to represent the correlation. If we want to avoid the values after decimal places, we can use round function.Consider the mtcars data in base R −Exampledata(mtcars) cor(mtcars)Output mpg cyl disp hp drat ...
Read MoreHow to create a list of an unordered combination of elements in a string vector in R?
An unordered combination of elements means that the combination of the values in a way that does not make any particular arrangement. For example, if we have three values one, two, and three then they can be arranged in the following way which is unordered −"one" "two" "three" "one" "two" "one" three" "two" "three" "one" "two" "three"Examplex
Read MoreHow to subtract one data frame from another in R?
If we have two data frames with same number of columns of same data type and equal number of rows then we might want to find the difference between the corresponding values of the data frames. To do this, we simply need to use minus sign. For example, if we have data-frames df1 and df2 then the subtraction can be found as df1-df2.Consider the below data frame −Examplex1
Read MoreHow to convert the repeated elements of strings in a vector to unique elements in R?
When we have repeated elements of strings and we want to use them as factor levels then it is okay but if we want to treat them individually then it is better to make each value a unique element. To do this, we can use make.unique function. For example, if we have a vector x that contains repeated string values then to make them unique, we can use make.unique(x).Examplex1
Read MoreHow to change a data frame with comma separated values in columns to multiple columns in R?
Mostly, we need to import the data from an outside source in R environment for analysis and these data can be recorded as comma separated values that represent rows. If we want to create the columns for the comma separated values then cSplit function of splitstackshape package can be used. In the below example, we have created a data frame with comma separated values then splitting those values as single value in each column.Consider the below data frame −Exampledf=data.frame(x=apply(matrix(rpois(200, 10), 20, 10), 1, paste, collapse=", ")) dfoutputx 1 8, 12, 7, 12, 10, 8, 11, 6, 8, 7 2 9, ...
Read MoreHow to standardize matrix elements in R?
The standardization is the process of converting a value to another value so that the mean of the set of values from which the original value was taken becomes zero and the standard deviation becomes one. To standardize matrix elements, we can use data.Normalization function of clusterSim package but we need to make sure that we set the type argument to n1 because that corresponds to standardization with mean zero and standard deviation 1.Loading clusterSim package −library("clusterSim")ExampleM1
Read MoreHow to display the values of two columns of an R data frame separately in a plot?
In general, the scatterplot is used to visualize the relationship between two columns of an R data frame but if we want to display the two columns separately not as a pair then we need to use matplot function. This function will create a plot for all the values in the two columns and represent them by their column number.Consider the below data frame −Exampleset.seed(222) x
Read MoreHow to create a subset of a matrix in R using row names?
When we create a matrix in R, the row names and column names are not defined but we can define them separately. If we want to take a subset of rows of a matrix then row numbers can be used within single square brackets but if we want to do it with the names then we need to specify those names.ExampleM1
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