We will learn:
1. Vector Names
2. Plotting One Vectors
This is part two of learning vectors in R programming language. If you haven't learned about the first part, you can start to learn vectors part one.
D. Vector Names
For instance, I have three values (e.g. red, yellow and black) which is stored in wordlist c vector. That will be written as follows;
wordlist <- c("red","yellow","black") # wordlist stored "red", "yellow" and "black" value.
As explained in Vector Access, when you need to pick one of the values, you can do like this:
Result:  "red","yellow","black"
Now, this time we will learn that "we can assign names to a vector's elements by passing a second vector filled with names to the "names" assignment function".(taken from. http://tryr.codeschool.com/levels/2/challenges/18) , as in:
names(wordlist) <- c("red","yellow","black")
(Note: to see more about names function in R, type:
When we want to access or pick one of the values, we can type like this:
From the example above, that means, that we can access the value directly beside our common way, as in:
From here, we also can change the position of "yellow" (that is: 2) to other position, for example, 7.
wordlist["yellow] <- 7
Now, see if it already changes:
or, with other way;
E. Plotting One Vector
This section, we will learn about barplot. What is it? barplot is R function which is used to create vertical or horizontal bars (e.g. chart) with vector values. For further and details about that, just ask R to answer by typing: -
Hint: Talking about Vectors will force you to remember 2 things: Variables and Values.
For example, we have ( again and again ... :p ) three values in c vector, they are: 3, 5 and 1, as follows:
1. Variable : stuDentS (warning: case sensitive!)
2. Value: 3, 5, 1.
in R, as usual, you can type:
Then, let's start using barplot (hurrayyyy):
Done! R will give us this amazing result!!!
Further, if you assign new names in the vector values (... say, barney, herman and adhya), R will take it as Labels which will be placed below each bars based on the order you give.
Then, R will give you this awesome chart!
Now, to show other types of chart, you can give range from 1 through 100, as in:
Here's the result:
See you on the next lesson :D, my best regards.