By now, we've used strings in a lot of examples, but we haven't spent time looking at them in detail yet. Before we dive into the nitty-gritty though, let's go over what we've seen so far and add a few more points. First, a quick refresher. A string is a data type in Python that's used to represent a piece of text. It's written between quotes, either double quotes or single quotes, your choice. It doesn't matter which type of quotes you use as long as they match. If we mix up double and single quotes, Python won't be too happy, and it'll return a syntax error, telling us it couldn't find the end of the string. A string can be as short as zero characters, usually called an empty string or really long. We also learned that we can use strings to build longer strings using the plus sign and action called concatenating. A less common operation is to multiply the string by a number, which multiplies the content of the string that many times like this. If we want to know how long a string is, we can use the len function which we saw in earlier videos. The len function tells us the number of characters contained in the string. We can use strings to represent a lot of different things. They can hold a username, the name of a machine, an email address, the name of a file, and any other text. A lot of the data that we'll interact with will be stored in strings, so it's important to know how to use them. There are tons of things we could do with strings in our scripts. For example, we can check if files are named a certain way by looking at the filename and seeing if they match our criteria, or we can create a list of emails by checking out the users of our system and concatenating our domain. I recently wrote a script that worked with a bunch of files and took different actions according to the name of each file. So the file ended in a certain extension say, .TXT , then my script would print it. If the file had a certain string and the name, say, test, then my script would ignore it and move on to the next thing and so on. The contents of a text file are also strings. A few months ago, I had to change the default values for a bunch of configuration options from true to false. So I wrote a function that would find the string true in a file and replace it with false. You can probably think of more examples where your code needs to handle strings, but to use strings effectively, we need to know what options are available to us in Python. In the next few videos, we'll cover some of the operations we can perform over strings, including how to access parts of them and modify them.