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Articles by Nizamuddin Siddiqui
Page 188 of 196
How to change the aspect ratio of a plot in ggplot2 in R?
The aspect ratio of a chart can be changed in ggplot2 and this will be useful if we want a smaller image of the chart. Sometimes, we don’t have large space where the chart will be pasted therefore this functionality becomes useful. Mostly, in research reports we see charts that are of small size, hence R becomes helpful to create charts that can be pasted in the desired space. This can be done with the help of theme function.ExampleConsider the below data frame −> set.seed(100) > x df library(ggplot2)Creating the plot with aspect ratio 4/3 −> ggplot(df, aes(x))+ + geom_bar()+ ...
Read MoreHow to deal with warning “removed n rows containing missing values” while using ggplot2 in R?
The warning “removed n rows containing missing values” occurs when we incorrectly specify the range of the values for X-axis or Y-axis. We can this range in ggplot function using scale_x_continuous(limits=c(?, ?)) for x axis and scale_y_continuous(limits=c(?, ?)) for y axis. If the range will be larger than the actual data range then there will be no warning otherwise, we will get the warning for the number of missing values.ExampleConsider the below data frame −> set.seed(2) > x y df library(ggplot2)Creating the plot with Y-axis limits from 0 to 5−> ggplot(df, aes(x, y))+ + geom_point()+ + scale_y_continuous(limits=c(0, 5)) Warning message: ...
Read MoreHow to create a bar chart using ggplot2 with facets that are in the order of the data in R?
Since visualization is an essential part of data analysis, we should make sure that the plots are created in a form that is easily readable for users. For this purpose, the facets in a bar chart helps us to understand the factor variable levels for another factor. To create such type of bar chart, we can use facet_grid function of ggplot2 package.ExampleConsider the below data frame −> set.seed(99) > y class quantity df library(ggplot2)Creating the plot with class on X-axis and y on Y-axis without any facet −> ggplot(df, aes(class, y))+ + geom_bar(stat="identity")OutputCreating the plot with class on X-axis, y ...
Read MoreHow to stop printing messages while loading a package in R?
There are some annoying messages we get while loading a package in R and they are not useful until and unless we are not loading a new package. Since these messages looks like outputs they might be confusing especially when we are analysing string data. Therefore, we must get rid of them.An example of message while loading BSDA package:>> library(BSDA)Loading required package − latticAttaching package − ‘BSDA’The following object is masked from ‘package:datasets’ −OrangeHere we have some messages while loading the package BSDA but we might not be interested in those messages if we are sure that package is installed ...
Read MoreHow to delete all files and folders from a path in C#?
For deleting all the folders and its respective directories we can make us System.IO namespace available in C#. The DirectoryInfo() class provides the details of all sub directories and file in a directory.ExampleLet us consider a directory Demo having two sub directories and has some files like below.using System.IO; namespace DemoApplication { class Program { static void Main(string[] args) { DirectoryInfo di = new DirectoryInfo(@"D:\Demo"); foreach (DirectoryInfo dir in di.GetDirectories()) { foreach (FileInfo file in dir.GetFiles()) { ...
Read MoreHow to verify an exception that has been thrown in unit testing C#?
There are two ways that we can verify an exception in unit testing.Using Assert.ThrowsExceptionUsing ExpectedException Attribute.ExampleLet us consider a StringAppend method which throws an exception needs to be tested.using System; namespace DemoApplication { public class Program { static void Main(string[] args) { } public string StringAppend(string firstName, string lastName) { throw new Exception("Test Exception"); } } }Using Assert.ThrowsExceptionusing System; using DemoApplication; using Microsoft.VisualStudio.TestTools.UnitTesting; namespace DemoUnitTest { [TestClass] public class DemoUnitTest { [TestMethod] public void ...
Read MoreHow to create a folder if it does not exist in C#?
For creating a directory, we must first import the System.IO namespace in C#. The namespace is a library that allows you to access static methods for creating, copying, moving, and deleting directories.It is always recommended to check if the Directory exist before doing any file operation in C# because the complier will throw exception if the folder does not exist.Exampleusing System; using System.IO; namespace DemoApplication { class Program { static void Main(string[] args) { string folderName = @"D:\Demo Folder"; // If directory does not exist, create it ...
Read MoreWhat is the difference between Static class and Singleton instance in C#?
StaticStatic is a keywordStatic classes can contain only static membersStatic objects are stored in stack.Static cannot implement interfaces, inherit from other classesSingletonSingleton is a design patternSingleton is an object creational pattern with one instance of the classSingleton can implement interfaces, inherit from other classes and it aligns with the OOPS conceptsSingleton object can be passed as a referenceSingleton supports object disposalSingleton object is stored on heapSingleton objects can be clonedSingleton objects are stored in Heap
Read MorePython - Write multiple files data to master file
File handling is an important part of any web application.Python has several functions for creating, reading, updating, and deleting files.To write to an existing file, you must add a parameter to the open()function −"a" − Append − will append to the end of the file"w" − Write − will overwrite any existing contentExampleimport os # list the files in directory lis = os.listdir('D:\python' '\data_files\data_files') print(lis) tgt = os.listdir('D:\python' '\data_files\target_file') file_dir ='D:\python\data_files\data_files' out_file = r'D:\python\data_files\target_file\master.txt' ct = 0 print('target file :', tgt) try: # check for if file exists # if yes delete the file # otherwise ...
Read MorePython - Working with .docx module
Word documents contain formatted text wrapped within three object levels. Lowest level- Run objects, Middle level- Paragraph objects and Highest level- Document object.So, we cannot work with these documents using normal text editors. But we can manipulate these word documents in python using the python-docx module.The first step is to install this third-party module python-docx. You can use pip “pip install python-docx”After installation import “docx” NOT “python-docx”.Use “docx.Document” class to start working with the word document.Example# import docx NOT python-docx import docx # create an instance of a word document doc = docx.Document() # add a heading of level 0 ...
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