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CSVs were and still are a very
popular format for importing and

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exporting data to and
from databases and spreadsheets.

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Much of the web though,
runs on another common and

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popular format, JSON, or
JavaScript Object Notation.

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No, I'm not trying to get
you to write JavaScript,

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Python's JSON module is very handy for
encoding and decoding data from JSON.

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You'll use this when you're
receiving information in your API or

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sending information to an API, or
maybe you just want to use it to read and

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write files on your server.

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JSON is pretty common for

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configuration files too,
regardless of how you're going to use it,

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it's a great format to know about, and
a great library to know how to use.

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Python's JSON library is pretty solid and
I think, pretty easy to use.

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Let's check out this JSON
file about a piece of art

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that I downloaded from
the Minneapolis Institute of Art.

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You can see that a lot of stuff in here,
I can read it like it's a dictionary and

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go, it's dated 1899, cool,
but I don't wanna do that.

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I wanna be able to do this in Python,
right?

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So I'm gonna make a new file and
I'm gonna call this art.py,

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and inside of here, first things first.

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We need to import the JSON module, so

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the JSON module has all of
our handy dandy stuff in it.

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So I'm going to open it up, what is this?

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148.json as art file.

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So I'm gonna open that up and
I'm gonna say art = jason.load(artfile),

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and then I'm gonna
print(art['description']).

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All right, cool?

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So let's go run this.

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And I get that it's a boat with two masts
in front of a bridge with a lift-gate,

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two row boats in water at left,
buildings at left, trees at right,

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that's the description I
got from the JSON file.

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Now that might not look like much but it's
really handy if you're dealing with tons

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of input from an outside source, or
lots and lots and lots of files.

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And you don't have to try and
turn plain-text files in Python Objects or

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anything like that through RegX or
some sort of, I don't even know,

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some sort of arcane incantation.

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The load method, which we used right here,
takes a file-like object and

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tries to turn that into
a Python object of some kind.

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In this case, because what we have here is
what we would call a dictionary in Python,

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it just creates a dictionary,
it creates an actual Python dictionary.

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If we had a list, an array for
JavaScript, then we would get a list

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in Python, another way that we can
do this is with the load s method.

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You'll probably hear people call
it loads instead of load s or

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load string, I call it loads all the time.

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Honestly, that's fine, that's what the
word is, but the way that it's spelled,

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what it is, is it's the way that we can
take a string with embedded JSON in it and

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turn that into a Python object.

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Let's try that out,
let's try it out down here in the shell.

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We'll do Python, import json and

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let's do nums = json.loads and

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then a string of 1,2, and 3.

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All right, and so
now if I do nums[2] I get the number 3,

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so we loaded the string in the JSON.

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In that string there was an array of
integers which the JSON module turned

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into a list of ints and
I think that's pretty handy.

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The opposite of load and
loads are the dump and

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dumps methods, so let's try them out.

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So we can do json.dumps([5, 4, 3, 2, 1]).

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No quote marks, and now, I get a string
which has the array of numbers in it,

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so it's kinda like I turned
the list into a string,

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I mean, it almost seems like I get
to str and then the list, right?

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And I could on something this simple,
but on something that's a little bit

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more complicated, you obviously
can't do that, let's try this.

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I'm gonna make myself into a dictionary,
so first_name is Kenenth,

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last_name is Love, and
my topic here at Treehouse Is Python.

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All right, so I can't just do str(me),

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I mean, I can but I don't get
exactly the right thing, right?

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So let's do json.dumps(me) and

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while it looks the same,
there is a difference because in JSON

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you have to have double quotes instead
of single quotes to make it valid.

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So this is valid JSON, what I did
before is not, and if I was to have

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numbers like that in there, we'd want
to change how those things worked.

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We could also easily send this string out
across the internet with no problems, so

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that's great,

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that's super handy, we could do something
similarly using the Dump method.

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But Dump goes directly into a file-like
object instead of into a string,

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so we have me, let's make Craig.

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So again, do first_name as Craig,

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last_name as Dennis, and
topic as Java all right?

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So we have me, and we have Craig,
and let's do with open

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teachers.json, and a for append,
although it doesn't really matter,

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cuz we're writing into this for
the first time, as teacherfile.

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Then we wanna say json.dump, and

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we're gonna dump an array of me and

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craig into teacherfile, all right?

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Let that run and now,
let's shrink that down, refresh this,

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if we checked out teachers.json
that the file that we just created.

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There's me, and
I misspelled my own name, and

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there's Craig, and
it made a list of objects.

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So that's pretty cool, that's super
awesome, the JSON module is amazingly

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handy for both encoding and decoding
data to and from files and strings.

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I find myself using it a lot with
various APIs on the web, and

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I bet that you will find it the same.