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Server Side Programming Articles
Page 1171 of 2109
What is the difference between ls() command and objects() command in R?
They are actually no difference between the two commands as they give the same result that is the number of objects in the current workspace. If we have five different type of objects say a data frame, a matrix, a list, a data.table object, and a vector then both the commands will give the names of these objects.ExampleConsider the below objects −> x1 x2 df1 df1Outputx1 x2 1 A A 2 D A 3 C D 4 A A 5 B C 6 B D 7 D D 8 D C 9 B D 10 B A 11 D B ...
Read MoreHow to detach a package in R?
To detach a package in R, we can simply use the detach function. But we need to remember that once the package will be detached there is no way to use any of the functions of that particular package. We make this mistake if we forget about detachment. For example, if we detach ggplot2 package using detach function detach(package:ggplot2, unload=TRUE) and again run the ggplot or qplot function then there will be an error.ExampleConsider the below data frame −> x y df dfOutputx y 1 -0.09124881 0.8106691 2 -0.20521435 -1.0067072 3 -1.07904498 1.3867400 4 1.34461945 -1.4676405 5 -0.21731862 0.5801624 6 ...
Read MoreHow to find the p-value using F statistic in R?
The F statistic has two degrees of freedom, one for the numerator and one for the denominator and the F distribution is a right-tailed distribution. Therefore, we need to use the F-statistic, the degrees of freedoms, and the lower.tail=FALSE argument with pf function to find the p-value for a F statistic.Examples> pf(5, 1, 99, lower.tail=F) > pf(5, 1, 24, lower.tail=F) > pf(5, 1, 239, lower.tail=F) > pf(5, 5, 239, lower.tail=F) > pf(5, 5, 49, lower.tail=F) > pf(12, 5, 49, lower.tail=F) > pf(120, 5, 49, lower.tail=F) > pf(120, 1, 49, lower.tail=F) > pf(120, 1, 149, lower.tail=F) > pf(3, 1, 149, lower.tail=F) ...
Read MoreHow to create boxplot for matrix columns in R?
To create a boxplot for data frame columns we can simply use boxplot function but it cannot be done directly for matrix columns. If we want to create boxplot for matrix columns then we need to convert the matrix into data frame and then use the boxplot function. For example, if we have a matrix called M then the boxplot for columns in M can be created by using boxplot(as.data.frame(M)).Example> M MOutput[,1] [,2] [,3] [,4] [,5] [1,] 1.688556 1.697216 1.9469573 1.873956 2.010246 [2,] 1.655357 1.927145 2.0937415 2.273638 1.966972 [3,] 1.886917 1.182852 2.0291452 2.507944 2.338664 [4,] 2.013053 1.995526 1.8122830 2.531708 2.483359 [5,] 1.812015 1.950053 1.8902859 2.453222 2.123253 [6,] 1.781764 1.786285 2.3384120 2.275382 2.509708 [7,] 1.836378 1.192781 1.5382031 2.012324 2.290340 [8,] 2.061482 1.705481 2.5542404 1.958202 1.991252 [9,] 2.162214 1.958862 1.8096081 1.810033 1.856942 [10,] 1.897020 1.614834 2.3407207 2.199068 1.807968 [11,] 2.491147 2.317192 2.4486029 2.131722 1.947841 [12,] 1.860307 1.932982 2.2034280 1.982581 2.720482 [13,] 1.814205 2.214286 1.6917036 1.854341 2.150684 [14,] 1.224437 1.800944 1.7600398 1.503382 2.775012 [15,] 2.309462 2.534766 1.5111472 2.058761 1.823550 [16,] 2.190564 1.588298 1.8854163 1.694651 1.939035 [17,] 2.521611 2.339012 2.2959581 2.501148 1.951673 [18,] 1.808799 2.314207 1.8704730 1.937851 1.877917 [19,] 2.476626 1.806194 2.7111663 2.156506 1.521197 [20,] 1.819725 1.633549 1.9438948 2.213533 2.247944 [21,] 2.412117 1.797531 2.5320892 1.889267 2.586912 [22,] 1.679395 2.276218 1.6120445 1.648766 1.889033 [23,] 2.286285 2.221312 0.9408758 1.896072 1.996449 [24,] 2.274975 2.398884 2.0146319 1.814092 2.350100 [25,] 2.106620 1.640401 1.6416454 2.452356 1.638885 [26,] 1.556329 1.706762 1.8324196 2.348518 1.593293 [27,] 2.171867 1.707615 1.9667116 2.191344 1.595531 [28,] 1.796751 2.753674 2.1741976 1.623239 2.399018 [29,] 2.635992 2.180735 2.2114669 2.258419 2.277367 [30,] 1.874671 2.113165 2.3653358 2.231705 1.919449Example> boxplot(as.data.frame(M))Output
Read MoreHow to change the width of whisker lines in a boxplot using ggplot2 in R?
In R, by default the whisker lines are as wide as the box of the boxplot but it would be great if we reduce that width or increase it because it will get attention of the viewer in that way. This can be done by using the width argument inside the stat_boxplot function of ggplot2 package. Check out the below example to understand how it works.ExampleConsider the below data frame −Example> x y df dfOutputx y 1 B 5 2 B 4 3 A 6 4 A 9 5 B 2 6 B 4 7 B 6 8 B 2 ...
Read MoreHow to create a column in an R data frame that contains the multiplication of two columns?
Sometimes we need the multiplication of two columns and create a new column so that the multiplication can be used further for analysis. For example, to calculate BMI we need mass and height and the height is squared, therefore, we would be needing the square of height. For this purpose, we can either multiply height with height or simply take the square both the ways work. Hence, if only have height column in an R data frame then we can multiply it with itself.ExampleConsider the below data frame −> set.seed(957) > x y z df dfOutputx y z 1 0 ...
Read MoreHow to create a residual plot in R with better looking aesthetics?
The default residual plot can be created by using the model object name in base R but that is not very attractive. To create a residual plot with better looking aesthetics, we can use resid_panel function of ggResidpanel package. It is created in the same way as the residual plot in base R, also it results in all the relevant graph in one window.ExampleConsider the below data frame −> x y df dfOutputx y 1 0.48508894 0.217379409 2 0.75113573 -0.657179470 3 -0.13075185 -0.549613217 4 -0.26867557 1.156736294 5 0.40407850 0.640387394 6 -0.23816272 -0.807847198 7 -0.57278583 0.600249694 8 -0.78222676 -0.711133218 9 1.70161645 ...
Read MoreCount trailing zeros in factorial of a number in C++
Given an integer number as input. The goal is to find the number of trailing zeroes in the factorial calculated for that number. A factorial of a number N is a product of all numbers in the range [1, N].We know that we get a trailing zero only if the number is multiple of 10 or has a factor pair (2, 5). In all factorials of any number greater than 5, we have a number of 2s more than 5s in prime factorization of that number. Dividing a number by powers of 5 will give us the count of 5s ...
Read MoreHow to create an empty data frame with fixed number of rows and without columns in R?
To create an empty data frame with fixed number of rows but no columns, we can use data.frame function along with the matrix function. That means we need to create a matrix without any column using matrix and save it in a data frame using data.frame function as shown in the below examples.Example1> df1 df1Outputdata frame with 0 columns and 10 rows Example2> df2 df2Outputdata frame with 0 columns and 100 rows Example3> df3 df3Outputdata frame with 0 columns and 39 rows Example4> df4 df4Outputdata frame with 0 columns and 20 rows Example5> df5 df5Outputdata frame with 0 columns and ...
Read MoreCount ways to express 'n' as sum of odd integers in C++
Given an integer n as input. The goal is to find the number of ways in which we can represent ‘n’ as the sum of odd integers. For example, if n is 3 it can be represented as sum ( 1+1+1 ) and (3) so total 2 ways.For ExampleInputn=6OutputCount of ways to express ‘n’ as sum of odd integers are: 8ExplanationThe ways in which we can express ‘n’ as sum of odd integers − 1. 1+1+1+1+1+1 2. 3+1+1+1 3. 1+3+1+1 4. 1+1+3+1 5. 1+1+1+3 6. 3+3 7. 1+5 8. 5+1Inputn=9OutputCount of ways to express ‘n’ as sum of odd integers ...
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