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R Programming Articles
Page 59 of 174
How to repeat a random sample in R?
The random sample can be repeated by using replicate function in R. For example, if we have a vector that contains 1, 2, 3, 4, 5 and we want to repeat this random sample five times then replicate(5, x) can be used and the output will be matrix of the below form:[, 1] [, 2] [, 3] [, 4] [, 5] [1, ] 1 1 1 1 1 [2, ] 2 2 2 2 2 [3, ] 3 3 3 3 3 [4, ] 4 4 4 4 4 [5, ] 5 5 5 5 5Example 1> x1 x1Output[1] 1 ...
Read MoreHow to set the legends using ggplot2 on top-right side in R?
The default position of legend in a plot created by using ggplot2 is right hand side but we can change the position by using theme function that has legend.position argument and legend.justification argument. To set the legend on top-right side we can use legend.position="top" and legend.justification="right".ExampleConsider the below data frame:Consider the below data frame:> x freq df dfOutputx freq 1 Mango 212 2 Guava 220 3 Pomegranate 218Loading ggplot2 package and creating bar chart with legend:> library(ggplot2) > ggplot(df, aes(x, freq, fill=x))+geom_bar(stat="identity")Output:Creating the bar chart with legend on top-right hand side of the chart:Example> ggplot(df, aes(x, freq, fill=x))+geom_bar(stat="identity")+theme(legend.position="top", legend.justification="right")Output:
Read MoreHow to find the cumulative sums by using two factor columns in an R data frame?
Generally, cumulative sums are calculated for a single variable and in some cases based on a single categorical variable, there are very few situations when we want to do it for two categorical variables. If we want to find it for two categorical variables then we need to convert the data frame to a data.table object and use the cumsum function to define the column with cumulative sums.ExampleConsider the below data frame:> set.seed(1361) > Factor1 Factor2 Response df1 df1OutputFactor1 Factor2 Response 1 A T2 9 2 B T1 8 3 B T1 2 4 A T2 3 5 B T1 ...
Read MoreHow to find the standard deviation if NA's are present in a column of an R data frame?
If there exists an NA in a vector or column of an R data frame, the output of the sd command for standard deviation results in NA. To solve this problem, we need to use na.rm=TRUE as we do it for vectors that do not contain missing values. For example, if we have a column of a data frame df defined as x that contains missing values then sd of x can be calculated as sd(df$x).ExampleConsider the below data frame:> set.seed(3521) > x df1 df1Outputx 1 NA 2 5.107864 3 4.797851 4 5.184345 5 4.680958 6 5.245151 7 5.760667 8 ...
Read MoreHow to remove a common suffix from column names in an R data frame?
To remove a common suffix from column names we can use gsub function. For example, if we have a data frame df that contains column defined as x1df, x2df, x3df, and x4df then we can remove df from all the column names by using the below command:colnames(df) x1Data x2Data x3Data df1 df1Outputx1Data x2Data x3Data 1 29.26500 26.64124 2.598983 2 21.82170 23.41442 4.134393 3 22.71918 25.21586 4.442823 4 19.88633 25.23487 3.338448 5 20.48989 23.33683 3.829757 6 29.07910 25.54084 3.519393 7 24.28573 23.67258 4.667397 8 27.99849 22.97148 4.100405 9 23.48148 25.36574 2.618030 10 26.39401 23.80191 4.235092 11 29.39867 24.36261 2.782559 12 30.11137 ...
Read MoreHow to extract the first highest occurring value in an R data frame column?
The highest occurring value is called the mode and there can be multiple modes in a variable. If we have multiple modes then we can find the first mode or first highest occurring value by using sort function. For example, if we have a vector x that contains more than two modes then the first mode can be found as:sort(table(df$x), decreasing=TRUE)[1]ExampleConsider the below data frame:> set.seed(36521) > x df1 df1Outputx 1 B 2 E 3 A 4 A 5 D 6 E 7 D 8 B 9 B 10 C 11 E 12 D 13 E 14 A 15 A ...
Read MoreHow to count the number of values that satisfy a condition in an R vector?
Sometimes we want to find the frequency of values that satisfy a certain condition. For example, if we have a vector say x that contains randomly selected integers starting from 1 and ends at 100, in this case we might want to find how many values are exactly equal to 10. This can be done by using which and length function.Example1> x1 x1Output[1] 5 7 3 3 2 7 3 7 6 3Example> length(which(x1==5)) [1] 1 > length(which(x1==7)) [1] 3 > length(which(x1==3)) [1] 4Example2> x2 x2Output[1] 4 1 5 5 5 3 8 9 8 4 8 1 6 3 ...
Read MoreHow to create a point chart for categorical variable in R?
The point chart of a categorical has points corresponding to the categories just like the bar chart has bars. If we want to create point chart for categorical variable then we just need to use geom_point function of ggplot2 package. For example, if we have a data frame df that contains categorical column x and frequency column defined sd freq then the point chart for the categories in x can be ggplot(df, aes(x, freq))+geom_point().ExampleConsider the below data frame:> set.seed(3521) > x freq df dfOutputx freq 1 B 2 2 C 12 3 A 8 4 D 12 5 C 8 ...
Read MoreHow to create colored barplot using ggplot2 without legend entries in R?
When we create a colored barplot using ggplot2 the legend entries are automatically created. If we want to create the plot without those legend entries then theme function can be used. For example, if we have a data frame df that contains x as categorical variable and y as count variable then barplot without legend entries can be created as:ggplot(df, aes(x, y, fill=x))+geom_bar(stat="identity")+theme(legend.position="none")ExampleConsider the below data frame:> x y df dfOutputx y 1 A 24 2 B 28 3 C 25 4 D 27 5 E 26Loading ggplot2 package and creating the barplot:> library(ggplot2) > ggplot(df, aes(x, y, fill=x))+geom_bar(stat="identity")Output:Creating the ...
Read MoreHow to create a staircase plot in R?
The simple staircase plot can be created by using geom_tile function of ggplot2 package. We just need to use the vector or the column for which we want to create the staircase plot in place of x and y as well. For example, if we have a column say x of an R data frame df then the staircase plot can be created as ggplot(df, aes(x, x))+geom_tile().ExampleConsider the below data frame:> x df dfOutputx 1 1 2 2 3 3 4 4 5 5 6 6 7 7 8 8 9 9 10 10Loading ggplot2 package and creating staircase plot:> ...
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