Understanding CSV Files

Hi, this is Gary with MacMost.com. Let's take a look at CSV files. 

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So CSV stands for Comma Separated Values. CSV files are a way to store data in a very simple format. They're basically plain text files that contain a spreadsheet. Each row of the text file is a separate row in the spreadsheet. Each column is separated by a comma. Thus Comma Separated Values. The advantage to a CSV file is it is not proprietary. It's not a Microsoft Excel file that can only be opened in Excel or an Apple Numbers file that can only be opened in Numbers. It's a very basic format that can be opened in either of those two apps or other spreadsheets like Goggle's Sheets. So when a website wants to provide some data in a very basic format that doesn't rely on the other person having a particular app a CSV file is a great way to do that. 

Here is a sample CSV file. If I were to Control Click on it and Open With, TextEdit, you could see how it's a very simple looking file. There's just each row here with commas for each column. Now your Mac is smart enough to know that if you QuickLook a CSV file then it comes up in a little table here. So you can see the data in it. It's not just going to show you the plain text. Yet you can edit the text in a Text Editor. So if I opened it in TextEdit and say change this value right here and Save it, now if I use QuickLook you can see that new value is there. Furthermore the default app for opening up a CSV file should be Numbers. If you double-click then it should open it up and you see it as a Numbers spreadsheet with the data from the CSV file in a single table. 

If Numbers isn't what you get when you click a CSV file you could always select the file, choose File, and then Get Info, and then go to Open With. Then you can change which app is used to open that file. Or if you select an app you can click the Change All button there and it will change it so that any CSV file that you double-click on will open in that app. 

So as I mentioned before you can Open With Numbers and it is probably the default app. But you can also open in any other spreadsheet app. I don't think there are any spreadsheet apps out there that wouldn't open a CSV file. So, for instance, I can open this in Microsoft Excel. You can see how it works just as well here. 

Creating a CSV file from scratch is easy to do. You can just open up a Text Editor, like TextEdit. Make sure you're in text editing mode. So, for instance, if you see make plain text here switch to that. In this case I'm already in Plain Text Mode. I can type in some information like this along as I keep track of the commas to make sure all of the columns will workout. I could Save this file. Then instead of saving with a .txt extension use .csv and save. Now when I double-click on this it will open up in Numbers and there's my data. 

Likewise when you download data from a website it almost always gives you a CSV option. So here I am at the US Census Bureau site. I want to download some data. Notice that I've got various options here. One of them is CSV. If I click here to download CSV I can download this file. Here it is. I can use QuickLook to preview it. I can double-click and it will open up in Numbers. 

Note that if I take a look at this file in TextEdit you could see it is a bit more complex than our simple examples from before. One of the things you'll notice is the use of quotes. So Quotes are used around any data. So when you have an open quote you can include any text you want and then a close quote. Then you would have a comma before the next value. To be safe a lot of CSV documents will just put every value in quotes. Even if it is just a plain number and doesn't need it. But you can see here an example of how commas are used inside the value. So if it wasn't for the quotes on either end it would process this as three separate numbers instead of one large number. 

In addition you could export from Numbers or any spreadsheet app as a CSV file. So you can go here to File, Export To and one of the options is CSV. I can Save this out. I'll save it. Calling it example 2. If I open this with TextEdit you can see the resulting data. It is just a plain text file and can now be opened in Excel, imported into Goggle Sheets, or in any other spreadsheet app. 

So if you use CSV files I hope that this gives you some background to be able to use them more effectively. Thanks for watching.