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R Programming Articles
Page 66 of 174
How to find the minimum and maximum of columns values in an R data frame?
The range function in R provides the minimum and maximum values instead of the difference between the two. Hence, we can find the minimum and maximum by using range function but for a data frame we cannot use it directly. Check out the below examples to understand how it works.Example1> set.seed(974) > x1 x2 x3 df1 df1Output x1 x2 x3 1 0 6 10 2 0 7 10 3 3 3 11 4 2 7 9 5 3 2 5 6 3 4 7 7 2 7 7 8 2 8 5 9 0 4 9 10 2 2 11 ...
Read MoreHow to find the mean of very small numbers in numeric form that are represented with scientific notation in R?
If we find the mean of scientific numbers then the result will be also in scientific notation. We can get rid of this problem by using options(scipen=999), once we will use this code in R console all the inputs that are in scientific notation will be converted to normal numeric form, including any calculation and if we want to go back to the scientific notation then options(scipen=0) can be used.Example> x1 mean(x1)Output[1] 4.436267e-22Example> options(scipen=999) > mean(x1)Output[1] 0.0000000000000000000004436267Example> x2 x2Output[1] 0.000000000000000000000000000000000000001010964 [2] 0.000000000000000000000000000068291679999999998 [3] 0.000000000000000000000000006026013000000000181 [4] 0.000000000000000000000000002702241000000000107 [5] 0.000000000000000000000042258669999999998179163 [6] 0.000000000000000000000000000000091949710000000 [7] 0.000000000000000000000000000000000000107406400 [8] 0.000000000000000000000000000000091949710000000 [9] 0.000000000000000000000003463124999999999951636 [10] 0.000000000000000000004305051000000000103323794 [11] 0.000000000000000000000001542657000000000059366 ...
Read MoreHow to create a plot using rgb colors in R?
The rgb colors are referred to red green and blue. This combination helps us to create many different colors. In R, we can use rgb function to create a plot using with different colors along with the image function. If we want to have a plot with rgb colors without any axes title or axes labels then the appropriate arguments should be used inside the image function as shown in the below example.ExampleConsider the below data frame:> set.seed(9991) > x1 x2 x3 df dfOutput x1 x2 ...
Read MoreHow to remove rows based on blanks in a column from a data frame in R?
Sometimes data is incorrectly entered into systems and that is the reason we must be careful while doing data cleaning before proceeding to analysis. A data collector or the sampled unit might enter blank to an answer if he or she does not find an appropriate option for the question. This also happens if the questionnaire is not properly designed or blank is filled by mistake. Also, if we have categorical variable then a control category might be filled with blank or we may want to have a blank category to use a new one at later stage. Whatever the ...
Read MoreHow to create a random vector in R that sums to 1?
To create a random vector that sums to 1, we can use uniform distribution. The main thing that needs to be done cautiously is we should include 0 in the vector with randomly generating uniform distribution values. Check out the below examples to understand how it can be done.Example1> x1 x1Output[1] 0.45490995 0.23826247 -0.07338489 -0.33361362 0.26125094 -0.45243689 [7] 0.05967125 0.43007076 0.04069027 0.37457976Example> sum(x1)Output[1] 1Example2> x2 x2Output[1] 1.84330339 -0.11622911 -0.15001654 0.07803346 -0.17353612 0.23651847 [7] -0.21121933 -0.30938763 0.44503222 -0.64249881Example> sum(x2)Output[1] 1Example3> x3 x3Output[1] 2.63249755 1.17230387 -0.28068787 0.58040911 -1.48530836 -0.04894802 [7] 0.66718009 0.13504265 -0.18253891 -0.49757615 1.63580429 -2.31002917 [13] 2.66256899 -2.40636756 2.03789127 0.13579276 -0.75107129 ...
Read MoreHow to standardized a column in an R data frame?
The standardization means converting a vector or column of an R data frame in a way such that the mean of the same becomes 0 and the standard deviation becomes 1, that is it should be converted to standard normal distribution. In R, it can be easily done with the help of scale function. Check out the below example to understand how it is done.ExampleConsider the below data frame:> set.seed(3665) > x1 x2 x3 x4 x5 x6 df dfOutputx1 x2 x3 x4 x5 x6 1 1.3958185 49.39843 128.5224 3 4.183664 2.33406246 2 1.0467979 48.90103 120.5796 7 3.526731 0.02043217 3 0.9190516 ...
Read MoreHow to create a bar plot using ggplot2 with one bar having black border in R?
The bar plot can be easily created with the help of geom_bar. But if we want to have a different border for a particular bar then we first need to create the bar plot and store it in an object. After that we need to add the original plot with the bar for which we want to have a black border. Check out the below example to understand how it can be done.ExampleConsider the below data frame:> Group Freq df dfOutput Group Freq 1 G1 18 2 G2 27 3 G3 24Loading ggplot2 package ...
Read MoreHow to find the mean of a square matrix elements by excluding diagonal elements in R?
There are many ways to find the mean of a matrix elements by excluding diagonal elements, this mean is actually the mean of lower triangular matrix and the upper triangular matrix. We can simply use mean function by creating a vector of lower and upper triangular matrix as shown in the below examples.Example1> M1 M1Output [, 1] [, 2] [, 3] [, 4] [1, ] 1 6 3 6 [2, ] 8 5 3 4 [3, ] 5 4 4 6 [4, ] 5 5 3 4 [5, ...
Read MoreHow to find the column means of a column based on another column values that represent factor in an R data frame?
If we have a column that represent factor then we might want to find the mean of values in other column(s) for the factor levels. This is helpful in comparing the levels of the factor. In R, we can find the mean for such type of data by using aggregate function. Check out the below examples to understand how it can be done.Example1Consider the below data frame:> x1 y1 df1 df1Output x1 y1 1 D 5.801197 2 B 3.432060 3 B 6.154168 4 A 5.466655 5 D 5.171689 6 C 5.175170 7 B 5.353469 8 D 4.840470 ...
Read MoreHow to subset rows of an R data frame using grepl function?
The grepl function in R search for matches to argument pattern within each element of a character vector or column of an R data frame. If we want to subset rows of an R data frame using grepl then subsetting with single-square brackets and grepl can be used by accessing the column that contains character values.Example1Consider the below data frame:> x1 y1 z1 df1 df1Output x1 y1 z1 1 A 0.8833979 5 2 B 0.5400075 1 3 C 0.6923827 3 4 B 1.5069186 2 5 B 0.8190962 2 6 B 0.8296171 1 7 B ...
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