Python Jumpstart by Building 10 Apps Transcripts
Chapter: App 9: Real Estate Analysis App
Lecture: Sketching out the Real Estate Data Miner App
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All right, let's write the first part of our real estate data mining application.
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And we'll follow my standard convention of having a main method, at the top here,
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and then using the main live template in PyCharm,
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just sort of use the proper import safe way of invoking it,
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now we are going to do a couple of things,
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we are going to as always define a print_header()
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and we'll just print out some basic stuff as usual,
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so here is a standard header which we'll call from up here,
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the next thing we need to do is get the data file,
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so let's write a method not the actual data but just the file name for the data,
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so notice down here,
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let's talk about where are we getting our data from,
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we have a data subfolder next to our program,
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and we have the Sacramento real estate transactions for 2008,
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so this turns out to be all of the real estate transactions
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that I could find for Sacramento in 2008.
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Personal individuals, no business stuff.
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So we want access to this file,
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now we want to use again our OS
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so we'll import OS and a lot of times we've been saying .path, .join
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and we would give it something like '.' for the current directory
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and then we would say data and then we would say the name of this,
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in PyChrm you can hit ctrl+t and it gives you a rename
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which is probably the easiest way to just copy the name there,
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but this '.' assumes that we are always using the working directory
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just above the data folder,
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we always want to look right next to this program for its data
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no matter where it's running so let's get the base folder in different way.
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We'll say base_folders os.path.dirname() and remember,
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there is an __file__, a __file__,
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implicit variable for every module that's going to say here is the full path,
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so we get the base folder and then we can just put base folder here, right,
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so now it doesn't matter where we are running our code,
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we'll always get back to this, and then we'll just return that,
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let's do a little format really quick, and let's get the file it's called filename
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say get data file and then just let's print this out really quick.
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All right, that looks correct, I have it on my desktop
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and then here is our 09 real estate data and so on.
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Perfect, so that should work for getting us the file
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now the next thing to do instead of this is to actually load the data
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so I'll just say data like this and we'll come back to what that means,
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I'll just say load file, so we are going to do this in a couple of ways,
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we'll start out with like really basic way
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and then we'll come back and do a little bit more.
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Ok, so we got our data sketched out,
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and the very last thing that we are going to do, after we loaded up,
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maybe we'll print it out for a minute but I guess we can go and write query data
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and that will just spit out the report and so on so feed it data, like so,
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and that's the last method we'll write, and then, move on.
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So there we have the basic structure for our app
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and I don't know if I have shown you this for a while in PyCharm
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but over here you can actually see the structure
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and jump around if you like that's kind of handy,
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even better when you have classes and hierarchies and these sorts of things,
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so next we are going to work on load data and actually parsing our csv file.
