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1.4 GSUB() and SUB()



1.4 GSUB() and SUB()

Hello and welcome back to the advanced course on R programming. In this tutorial, we are going to deal with factor variables, the revenue and expenses ones and learn how to convert them into non-factor variables.



because as we can see, they are just numeric variables which contain information on dollar amount but it is recognized as factor, same with revenue and growth.It is mainly due to presence of word 'Dollars' in variable Expenses, presence of sign '$' and '%' in variables Revenue and Growth respectively.We have to convert it into numeric, but for that we will function SUB() and GSBU().

We will get the details on executing following command

 

So, what does these functions do is that they look for pattern and replace it with the desired pattern. The difference between SUB() and GSUB() is that, sub() replaces  just the first instance but gsub() replaces all the instances.. Hence, lets go ahead and try these functions out.



We will start with the expenses column in which we want to replace " Dollars" (make a note of empty space before word Dollars) with nothing.

Hence, lets run the following line.

and you will see that, the Dollars is removed from the column Expenses.

Now we have to replace the commas in the same column. Repeat the process similarly

Now, you can see that expenses has no longer commas. Lets check the str() on fin again.


We will see that, expenses is no longer a factor but it is of type character now.

Now lets deal with the variable Revenue. We will use the same gusb() as before with a slight change.

Please note that, '$' is itself a special character, so to make R recognize this sign as a part of a value in variable we use escape sequence, which is two backslashes in the variable Revenue.

Let's remove the commas now. It will also be converted into the type Character. 

We will have to repeat the same process for Growth variable as well.

Now we have all three variables in the type character, now we can very easily convert them in numeric with the function as.numeric().

Now, these three variables are being actually recognized as numeric, which is exactly what we wanted.

Here is the complete code.
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