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R Programming Articles
Page 54 of 174
How to create horizontal legend using ggplot2 in R?
The default legend direction is vertical but it can be changed to horizontal as well and for this purpose we can use legend.direction argument of theme function of ggplot2 package. For example, if we want to create a bar chart with x as categories and y as frequencies tjat are contained in a data frame df then the bar chart with horizontal legends for categories in x can be created as −ggplot(df, aes(x, y, fill=x))+geom_bar(stat="identity")+theme(legend.direction="horizontal")ExampleConsider the below data frame −> x y df dfOutputx y 1 A 27 2 B 25 3 C 28Loading ggplot2 package and creating the bar ...
Read MoreHow to set the X-axis labels in histogram using ggplot2 at the center in R?
The boundary argument of geom_histogram function and breaks argument of scale_x_continuous function can help us to set the X-axis labels in histogram using ggplot2 at the center. We need to be careful about choosing the boundary and breaks depending on the scale of the X-axis values. Check out the below example to understand how it works.ExampleConsider the below data frame −Example> x df dfOutputx 1 5 2 7 3 6 4 4 5 7 6 7 7 10 8 3 9 6 10 6 11 5 12 4 13 4 14 6 15 7 16 4 17 1 18 11 ...
Read MoreHow to find the number of occurrences of unique and repeated characters in a string vector in R?
To find the number of occurrences of unique characters in a string vector, we can use table function with the combination of rle and strsplit. For example, if we have a string vector x that contains some unique and repeated values then it can be created by using the below command −table(rle(strsplit(x, "")[[1]]))Example 1> x1 x1Output[1] "ABDAJFSDAVCJDDAJFKDSAFKDSJKCJCCJCJDKD"Example> table(rle(strsplit(x1, "")[[1]]))Outputvalues lengths A B C D F J K S V 1 5 1 3 6 3 7 4 3 1 2 0 0 1 1 0 0 0 0 0It means A of length 1 occurred 5 times and A of ...
Read MoreHow to create a random sample of months in R?
Random samples can be created by using sample function and months in a year can be generated with the help of month.name function. Therefore, if we want to create a random sample of months then month.name can be used with sample function as sample(month.name) and if the size of the sample is larger than 12 then replace=TRUE argument should be used.Examplesx1
Read MoreHow to convert 12-hour time scale to 24-hour time in R?
Dealing with time data is not an easy task, it is sometimes difficult even in built-in analytical softwares, thus it won’t be easy in R as well. Mostly, we record time on a 12-hour time scale but in some situations, we need 24-hour time scale. Therefore, if we want to convert 12-hour time scale to 24-hour time scale then format function can be used with as.POSIXct. Look at the below examples, to understand it better.Example1Time1
Read MoreHow to find the position of minimum value in a vector that contains integers as strings in R?
If integer vector is read as strings and we want to find the position of the minimum value in that vector then we need to use as.numeric along with the vector to read it as a numeric vector then use which function for finding the position of the minimum value. For example, if we have a vector x that contains first ten integers as strings then to find the position of the minimum we can use which(as.numeric(x)==min(as.numeric(x))).Example1x1
Read MoreHow to find minimum value in a numerical vector which is written as a character vector in R?
To find the minimum value of a numeric vector we can directly use min function but if the values are read with double-inverted commas then min function does not work. In this case, we will have to use as.numeric with the vector name so that it can be converted to numeric form before finding the minimum value. For example, if we have a character vector that contains 1, 2, 3, and 4 then the minimum can be found as min(as.numeric(x)).Example1x1
Read MoreHow to create a vector with lowercase as well as uppercase letters in R?
To create a vector with lowercase we can use the word letters and for uppercase the word LETTERS is used in R. If we want to create a vector with both type of letters then both of these words can be combined using c function and if want to create a vector with randomly sampled values of lowercase and uppercase letters then sample function can be used.Examples> x1 x1Output[1] "A" "B" "C" "D" "a" "b" "c" "d"Example> x2 x2Output[1] "A" "B" "C" "D" "E" "F" "G" "H" "I" "J" "K" "L" "M" "N" "O" "P" "Q" "R" "S" [20] "T" ...
Read MoreHow to replace numbers with ordinal strings for a survey in an R vector?
The easiest way to replace numbers with ordinal strings is using ifelse function. The ifelse function in R works as ifelse(test_expression, x, y). Here, test_expression must be a logical vector or an object that can be coerced to logical). The return value is a vector with the same length as test_expression.Example1> x1 x1Output[1] 1 1 1 0 1 0 0 1 1 1 0 0 1 0 1 0 0 1 1 0 0 1 1 1 1 0 0 0 0 1 1 1 0 1 1 0 1 [38] 0 1 1 0 0 1 0 1 1 ...
Read MoreHow to extract the names of vector values from a named vector in R?
How to extract the names of vector values from a named vector in R?The names of vector values are created by using name function and the names can be extracted by using the same function. For example, if we have a vector called x that contains five values(1 to 5) and their names are defined as first, second, third, fourth and fifth then the names of values in x can be extracted by using names(x)[x==1].Example1> x1 names(x1) x1Outputone two three four 1 2 3 4Example> names(x1)[x1==1]Output[1] "one"Example> names(x1)[x1==2]Output[1] "two" Example> names(x1)[x1==3]Output[1] "three"Example> names(x1)[x1==4]Output[1] "four" Example2> x2 x2Output [1] 3 5 ...
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