Article Categories
- All Categories
-
Data Structure
-
Networking
-
RDBMS
-
Operating System
-
Java
-
MS Excel
-
iOS
-
HTML
-
CSS
-
Android
-
Python
-
C Programming
-
C++
-
C#
-
MongoDB
-
MySQL
-
Javascript
-
PHP
Articles by Nizamuddin Siddiqui
Page 155 of 196
How to subset one or more sub-elements of a list in R?
A list contains different type of elements and each of the them can have varying elements. To subset these sub-elements we can use sapply function and use c to subset the number of corresponding sub-elements. For example, if we have a list that contains five elements and each of those elements have ten sub-elements then we can extract 1, 2, 3 etc elements from sub-elements.ExampleConsider the below list − Live Demox1
Read MoreHow to convert the correlation matrix into a data frame with combination of variables and their correlations in R?
The cor function in R helps us to find the correlation matrix from a data frame or a matrix but the output of it always a matrix as intended. We might want to convert that matrix into a data frame which consists of all combination of variables with their correlation value. It can be done by reading the correlation matrix with as.table and converting that table into a data frame with as.data.frame.ExampleConsider the below data frame − Live Demox1
Read MoreHow to find the difference between row values starting from bottom of an R data frame?
If an R data frame contains all numerical columns and we want to find the difference between row values then we will lose first row of the data frame because that will not be subtracted from any row. This can be done by using head function and minus sign. It will work as subtracting the second last row from the last row, then subtracting third last row from the second last row and so on.ExampleConsider the below data frame − Live Demox1
Read MoreHow to reverse the X-axis labels of scatterplot created by using ggplot2 in R?
ExampleThere exists a possibility that one of the variables is recorded in an opposite manner and we want to create a scatterplot using that variable. Therefore, we would need to reverse that variable while plotting. Suppose that variable is an independent variable, hence it will be plotted on X-axis. Thus, to reverse the X-axis labels we can use scale_x_reverse function of ggplot2 package.Consider the below data frame −Example Live Demox
Read MoreHow to calculate weighted mean in R?
Weighted mean is the average which is determined by finding the sum of the products of weights and the values then dividing this sum by the sum of total weights. If the weights are in proportion then the total sum of the weights should be 1. In base R, we have a function weighted.mean to find the weighted mean in which we just need to pass the vector of values and the vector of weights.Examples Live Demox1
Read MoreHow to change the adjustment of the plot title using ggplot2 to align it above the Y-axis labels in R?
When we create a plot and put a title above it, the alignment of the title is left-adjusted by default and that lies on the edge of the plot area. But sometimes, we want to display the title on the above side of the Y-axis labels, therefore, we can use theme function and set the hjust argument accordingly.ExampleConsider the below data frame − Live Demox
Read MoreHow to create bar plot of means with error bars of standard deviations using ggplot2 in R?
If we have summary data for a group variable then we might want to look at the errors or say differences between mean and standard deviations visually, therefore, we can create a bar plot with error bars of standard deviations. This can be done by using geom_errorbar function of ggplot2 package.ExampleConsider the below data frame − Live DemoGroup
Read MoreHow to add a vertical line with some value on a scatterplot created by ggplot2 in R?
When we draw a scatterplot, there might be some crucial points that we would want to display, hence we create a vertical or horizontal based on our objective. These vertical or horizontal lines can be drawn by using geom_vline or geom_hline function of ggplot2 but to add some value with them we can use geom_text function.ExampleConsider the below data frame − Live Demo> x y df dfOutput x y 1 1.2474363 -0.15892165 2 1.7511870 -1.18938250 3 -1.3001612 -0.32313571 4 -1.4220049 1.52915756 5 0.4355646 0.18282983 6 0.3128323 0.16467130 7 1.5099580 1.15199751 8 -0.4907705 -1.98635182 9 -1.4249190 ...
Read MoreHow to create a bar plot using ggplot2 with percentage on Y-axis in R?
Mostly, the bar plot is created with frequency or count on the Y-axis in any way, whether it is manual or by using any software or programming language but sometimes we want to use percentages. It can be done by using scales package in R, that gives us the option labels=percent_format() to change the labels to percentage.ExampleConsider the below data frame − Live Demo> x df dfOutput x 1 2 2 3 3 3 4 1 5 2 6 4 7 4 8 4 9 2 10 3 11 3 12 4 13 3 14 4 15 4 16 1 17 3 ...
Read MoreHow to replace a value in an R vector?
To replace a value in an R vector, we can use replace function. It is better to save the replacement with a new object, even if you name that new object same as the original, otherwise the replacements will not work with further analysis. As you can see in the object x5(in examples), when we replaced 5 with 3, the previous replacement of -1 with 0 returned as in original vector. Therefore, we should save it in a new object.Examples Live Demo> x1 x1Output[1] 1 2 3 4 5 6 7 8 9 10 > replace(x1, x1==5, 10)Output[1] 1 2 3 ...
Read More