Hi. Welcome to the first video in our series on string R, which is the Tidyverse package to process strings. Now, a string is something that will start with being close to the double-quotes. If I tried to put a quote mark inside of those, it's not done, so it's going to give me an error because it thinks it's the end of a string and the start of a new string. In order to get around that, what I do is a backslash, which says escape and do that. What you see printed to the screen shows me the printed representation. If I want to see what's actually being interpreted, what the raw contents of the string are, I would use the right lines command. When I do that, you can see that what is contained in the string, which is the quote mark. Now, I could also do write lines, and instead of putting the double quote in there, I could put a single quote mark, and then I don't have to escape. Or I could do the same thing by using single quotes around a double quote. Because those are different, it basically does the escape for you. Here we see, I'm storing a vector in x, it has two strings in it. If I look at x, it shows me the printed representation, but if I do write lines, it will show me what's contained in those. You see the first one, it escapes and shows me what's in there and then it escapes and shows me the backslash mark. Now I'm going to show you a different string. Here I'm going to do a vector, which is a character vector, and if I look at that, I see there's what's in my vector. If I did string length of x, it tells me how many characters are each one. Whereas if I do the length of x, it's going to tell me that x is a vector of three items. Or I could do in characters of x, which tells me the same thing as the string length. Now let's look at ways that we can put strings together. String_C, you'll notice that all the string are verbs begin with str underscore that so you can start typing them and it'll prompt you with all of the possibilities. If I did str_c, which a string concatenate, it puts them together with no space between them. I can instead tell it I want to concatenate these strings, but I'm going to specify a separator. Here I'm specifying that I want the semicolon and a space to separate the strings. I can do a similar command, a very similar command in base R is the paste command. If I did paste or I could do the same thing with a paste0, and that puts them together without any space between them. I can also use string concatenate, watch this one. I'll do string concatenate, and I'll tell it I want the string, o no, and then I want x. Now, remember, x is three elements long, and then again, well, look what it did, is it replicates, o no, and again, to be the same length as I had before and here as a string in between and puts the semicolon between the items. It took the first element of x and put it in and then repeated the, o no, the second element of x, again repeats, o no, the third element of x and again. We can also use the backslash to write characters that are not part of the regular keyboard. For instance, I can look at that character. You see that is the Greek letter mu, so I can represent other characters and you can get a full listing of those online. That's going to be the end of Video 1. We will pick up with Video 2, which we'll talk about sub-setting strings.
