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Articles by Nizamuddin Siddiqui
Page 119 of 196
How to perform cartesian join for two data.table objects in R?
The cartesian join is the joining of two objects that creates the combination of each value in object with all the values in the other object. For example, if we have a vector x that contains 1, 2, 3 and the other object y contains a, b, c then the cartesian join will be 1a, 2a, 3a, 1b, 2b, 3b, 1c, 2c, and 3c. Check out the below examples to understand how it can be done.Example> library(data.table) > DT1 DT1Output x 1: 1 2: 2 3: 3 4: 4Example> DT2 DT2Output y 1: 25 2: ...
Read MoreHow to find the column number of minimum values in each row for a data frame in R?
To find the column number of minimum values in each row for a data frame, we can use apply function but if we want to return the output in tabular form then matrix function should be used. For example, if we have a data frame df then our problem can be solved by using the code: as.matrix(apply(df, 1, which.min)).ExampleConsider the below data frame:Live Demo> set.seed(37) > x1 x2 x3 x4 x5 df1 df1Outputx1 x2 x3 x4 x5 1 1 2 4 9 3 2 0 5 8 10 4 3 1 3 8 6 1 4 1 5 5 8 ...
Read MoreHow to replace numbers with ordinal strings for a survey in an R vector?
The easiest way to replace numbers with ordinal strings is using ifelse function. The ifelse function in R works as ifelse(test_expression, x, y). Here, test_expression must be a logical vector or an object that can be coerced to logical). The return value is a vector with the same length as test_expression.Example1Live Demo> x1 x1Output[1] 1 1 1 0 1 0 0 1 1 1 0 0 1 0 1 0 0 1 1 0 0 1 1 1 1 0 0 0 0 1 1 1 0 1 1 0 1 [38] 0 1 1 0 0 1 0 1 ...
Read MoreHow to create a blank csv file in R?
We can create a blank csv file using a single line code in R and the function that can do this is cat. If we want to have the file blank then NULL value will be passed inside the function and the file name must be used. For example, if we want to create a blank file named as BlankCSV then it can be created by using the below code:> cat(NULL, file="BlankCSV.csv")Output:This is the output from documents folder of the system where all the R files are stored by default(we can change that location if we want to):The output of ...
Read MoreHow to check if values in a column of an R data frame are increasingly ordered or not?
The values are increasingly ordered if the first value is less than the second, the second is less than the third, the third is less than the fourth, the fourth is less than the fifth, and so on. In base R, we have a function called is.unsorted that can help us to determine whether the values in a column of an R data frame are increasingly ordered or not. Check out the below examples to understand how it works.Example1Live Demo> set.seed(3257) > x df1 df1Output x 1 9 2 8 3 8 4 7 5 10 6 2 7 ...
Read MoreHow to display the curve on the histogram using ggplot2 in R?
Mostly, we use histogram to understand the distribution of a variable but if we have an overlay line on the histogram that will make the chart smoother, thus understanding the variation will become easy. To display the curve on the histogram using ggplot2, we can make use of geom_density function in which the counts will be multiplied with the binwidth of the histogram so that the density line will be appropriately created.ExampleConsider the below data frame:Live Demo> x df head(df, 20)Output x 1 4 2 5 3 6 4 4 5 9 6 ...
Read MoreHow to create a bar chart using plotly in R?
Plotly in R is a package specifically designed to create highly-interactive and publication-quality charts. The chart can be created by using plot_ly function of the package and there are three main arguments of plot_ly defined as x, y, and type, where x refers to the X-axis, y refers to the Y-axis and type refers to the chart type but the axes values are stored in a data frame or itself a shared.ExampleLoading plotly package:> library(plotly)Consider the below data frame:Live Demo> x count df dfOutputx count 1 A 321 2 B 324 3 C 320 4 D 328Creating the bar plot ...
Read MoreHow to create a covariance matrix in R?
To create a covariance matrix, we first need to find the correlation matrix and a vector of standard deviations is also required. The correlation matrix can be found by using cor function with matrix object. For example, if we have matrix M then the correlation matrix can be found as cor(M). Now we can use this matrix to find the covariance matrix but we should make sure that we have the vector of standard deviations.Example1Live Demo> M1 M1Output [, 1] [, 2] [, 3] ...
Read MoreWhy scale_fill_manual does not fill the bar with colors created by using ggplot2 in R?
We can manually fill the color of bars in a bar plot which is created by using ggplot2 but for this we would be needing color aesthetics already used for the bars. That means we need to use filling of bars inside aes of ggplot2 and then the colors can be mentioned inside the scale_fill_manual function.ExampleConsider the below data frame:Live Demo> x count df dfOutputx count 1 A 321 2 B 324 3 C 320 4 D 328Loading ggplot2 package and creating bar plot:Example> library(ggplot2) > ggplot(df, aes(x, count))+geom_bar(stat="identity")Output:Creating the bar plot by using scale_fill_manual:Example> ggplot(df, aes(x, count))+geom_bar(stat="identity")+scale_fill_manual(values=c("blue", "green", "grey", ...
Read MoreHow to determine if C# .NET Core is installed?
The following options are for dotnet by itself. For example, dotnet −−info. They print out information about the environment if not installed it will throw error.−−infoPrints out detailed information about a .NET Core installation and the machine environment, such as the current operating system, and commit SHA of the .NET Core version.−−versionPrints out the version of the .NET Core SDK in use.−−list−runtimesPrints out a list of the installed .NET Core runtimes. An x86 version of the SDK lists only x86 runtimes, and an x64 version of the SDK lists only x64 runtimes.−−list−−sdksPrints out a list of the installed .NET Core ...
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