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Articles by Nizamuddin Siddiqui
Page 130 of 196
How do I overload the [] operator in C#?
The [] operator is called an indexer.An indexer allows an object to be indexed such as an array. When you define an indexer for a class, this class behaves similar to a virtual array. You can then access the instance of this class using the array access operator ([ ]).Indexers can be overloaded. Indexers can also be declared with multiple parameters and each parameter may be a different type. It is not necessary that the indexes have to be integers.Example 1static void Main(string[] args){ IndexerClass Team = new IndexerClass(); Team[0] = "A"; Team[1] = "B"; Team[2] ...
Read MoreHow to check whether you are connected to Internet or not in C#?
There are many ways to check whether internet is connected to a machine in C# or not. Make use of System.Net namespace which provides common methods for sending data to and receiving data from a resource identified by a URI. The WebClient or HttpClient class provides common methods for sending data to or receiving data from any local, intranet, or Internet resource identified by a URI. Here in the below example we have used (OpenRead)Returns the data from a resource as a Stream.Checks by hitting the url "http://google.com/generate_204" if success return true else false.The below example runs in the loop ...
Read MoreHow to exclude extra margin between points and the axes for a plot created by using ggplot2 in R?
In a plot created by using ggplot package there exists an extra area around all the sides of the plot which uses extra space, thus we might want to get rid of that space by removing that extra margin area. It can be done by setting the scale for both the axes to zero with the help of scale_x_continuous and scale_y_continuous function.Consider the below data frame −Example Live Demoset.seed(151) x
Read MoreHow to find the intersection between two or more lists in R?
The intersection of lists means the elements that are unique and common between the lists. For example, if we have a list that contains 1, 2, 3, 3, 3, 2, 1 and the other list that contains 2, 2, 1, 2, 1 then the intersection will return only those elements that are common between the lists and also unique, hence for this example we will get 1 and 2. In R, we can do this by using intersection function along with Reduce function.Consider the below lists −Example Live DemoList1
Read MoreHow to apply manually created x-axis labels in a histogram created by hist function in R?
When we generate a histogram in R using hist function, the x-axis labels are automatically generated but we might want to change them to values defined by researchers or by any other authority. Therefore, firstly we need to create the histogram by ignoring the labels and then axis function can be used for new values.Consider the below vector x and create a histogram of x by ignoring x-axis labels −Exampleset.seed(1999) x
Read MoreHow to find the sum of diagonal elements in a table in R?
The sum of diagonal elements could be required in matrix analysis therefore, we can convert the matrix into a table and find the sum of diagonal elements. This can be easily done by using sun function by extracting diagonal elements of the table using diag function. For example, if we have a table T then the sum of diagonal elements of T can be found as sum(diag(T)).Example Live DemoTable1
Read MoreHow to create multiple plots of different sizes in base R?
Often, we have multiple values, vectors or columns of an R data frame that needs to be plotted on a single graph so that we can compare them at the same time or they have some kind of relationship among them. Therefore, we can use layout function along with matrix function to divide the plot window as shown in the below exampleConsider the below layout and plot of individual values −Examplelayout(matrix(c(1, 2, 3, 3, 4, 5, 6, 6), nrow=4, ncol=2, byrow=FALSE)) plot(500) plot(525) plot(530) plot(531) plot(540) plot(528)OutputChanging the layout and creating the plots −Examplelayout(matrix(c(1, 2, 3, 3, 4, 5, 6, ...
Read MoreHow to perform fisher test in R?
The fisher test helps us to understand whether there exists a significant non-random relationship among categorical variables or not. It is applied on contingency tables because these tables are used to represent the frequency for categorical variables and we can apply it on a matrix as well as matrices have the similar form. In R, we can use fisher.test function to perform the fisher test.Example Live DemoM1
Read MoreHow to remove everything before values starting after underscore from column values of an R data frame?
If a column in an R data frame contain string values that are separated with an underscore and stretches the size of the column values that also contain common values then it would be wise to remove underscore sign from all the values at once along with the values that is common. This will help us to read the data properly as well as analysis will become easy. For this purpose, we can use gsub functionConsider the below data frame −Example Live Demoset.seed(191) ID
Read MoreHow to remove rows from data frame in R based on grouping value of a particular column?
If we have a grouping column in an R data frame and we believe that one of the group values is not useful for our analysis then we might want to remove all the rows that contains that value and proceed with the analysis, also it might be possible that the one of the values are repeated and we want to get rid of that. In this situation, we can do subsetting of the data frame using negation and single square brackets.Example Live Demoset.seed(1212) x
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