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 54 of 196
How to remove names from a named vector in R?
To assign names to the values of vector, we can use names function and the removal of names can be done by using unname function. For example, if we have a vector x that has elements with names and we want to remove the names of those elements then we can use the command unname(x).Example1> x1 names(x1) x1OutputG K N V P F F A P D L N K J V H S L F C M F H T I V 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 ...
Read MoreHow 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 detect a binary column defined with 0 and 1 in an R data frame?
If a column in an R data frame has only two values 0 and 1 then we call it a binary column but it is not necessary that a binary column needs to be defined with 0 and 1 only but it is a general convention. To detect a binary column defined with 0 and 1 in an R data frame, we can use the apply function as shown in the below examples.ExampleConsider the below data frame −x1
Read MoreWhat are some examples of data sets with missing values in R?
Instructors/educators often need to teach missing value imputation to their students; hence they require datasets that contains some missing values or they need to create one. We also have some data sets with missing values available in R such as airquality data in base R and food data in VIM package. There could be many other packages that contain data sets with missing values but it would take a lot of time to explore them. Thus, we have shared the example of airquality and some data sets from VIM package.Example 1head(airquality, 20)Output Ozone Solar.R Wind Temp Month Day 1 41 ...
Read MoreHow to concatenate string vectors separated with hyphen in R?
The concatenation of string vectors will create combination of the values in the vectors thus, we can use them for interaction between/among the vectors. In R, we can use expand.grid along with apply to create such type of combinations as shown in the below examples.Example 1x1
Read MoreHow to match the names of a vector in sequence with string vector values in another vector having same values in R?
If we want to match the names of a vector in sequence with string vector values in another vector having same values then pmatch function can be used. The pmatch function means pattern match hence it matches all the corresponding values and returns the index of the values. Check out the below examples to understand how it works.Examplex1
Read MoreHow to set the Y-axis tick marks using ggplot2 in R?
The default value of Y-axis tick marks using ggplot2 are taken by R using the provided data but we can set it by using scale_y_continuous function of ggplot2 package. For example, if we want to have values starting from 1 to 10 with a gap of 1 then we can use scale_y_continuous(breaks=seq(1,10,by=1)).ExampleConsider the below data frame: x
Read MoreHow to add a rank column in base R of a data frame?
Ranking of a variable has many objectives such as defining order based on hierarchy but in data science, we use it mainly for analyzing non-parametric data. The ranking of a variable in an R data frame can be done by using rank function. For example, if we have a data frame df that contains column x then rank of values in x can be found as rank(df$x).ExampleConsider the below data frame: x1
Read More