dripper 1.2

Cleaning your messy data.

Contents

• Getting started
• Installation
• Basics
• Advanced
• CHANGES

Getting started

Consider cleaning up some messy data. Here is a deep nested dictionary containing lots of unnecessary nesting and tuple.

some_messy_data = {
    "body": {
        "article": {
             "articlesbody": {
                 "articlesmeta": {
                     "articles_meta_3": "Monty Python",
                 }
             }
        },
    },
    "published": {
        "datetime": ("2014-11-05", "23:00:00"),
    }
}

Values you want are 'Monty Python' and '2014-11-05', should be named 'title' and 'published_date'

Now let the hack begin with the dripper.

• Defile declaration dictionary
• Create dripper object by dripper.dripper_factory
• Drip essential data

# Define
 declaration = {
    "title": ("body", "article", "articlesbody", "articlesmeta", "articles_meta_3"),
    "published_date": ("published", "datetime", 0)
}

# Create
import dripper
d = dripper.dripper_factory(declaration)

# And drip
dripped = d(some_messy_data)

assert dripped == {
    "title": "Monty Python",
    "published_date": "2014-11-05",
}

Installation

Just use pip to install

pip install dripper

Requirements

dripper won’t require any kind of outer libraries. Supporting Python versions are:

• Python 2.7
• Python 3.3
• Python 3.4
• Python 3.5

Basics

Above example is not all features of dripper. It is created to handle various data to clean up.

As value

from dripper import dripper_factory
declaration = {
    "title": ("meta", "meta1")
})
d = dripper_factory(declaration)
d({"meta": {"meta1": "Monty Python"}}) == {"title": "Monty Python"}

Also you can specify string or integer directly. It is as same as one-element tuple.

from dripper import dripper_factory
declaration = {
    "title": "meta"
})
d = dripper_factory(declaration)
d({"meta": "Monty Python"}) == {"title": "Monty Python"}

As dict

dripper can define nested dictionary. Just pass nested dictionary to dripper_factory.

from dripper import dripper_factory
declaration = {
    "article": {
        "title": ["meta", "meta1"],
    }
})
d = dripper_factory(declaration)
d({
    "meta": {
        "meta1": "Monty Python",
    },
}) == {
    "article": {
        "title": "Monty Python",
    }
}

You can apply '__source_root__' to set root path for dripping.

declaration = {
    "article": {
        "__source_root__": ("body", "meta"),
...
        "title": "meta1",
        "author": ("meta2", "meta22"),
    }
})
d = dripper_factory(declaration)
d({
    "body": {
        "meta": {
            "meta1": "Monty Python",
            "meta2": {"meta22": "John Due"}
        }
    }
}) == {
    "article": {
        "title": "Monty Python",
        "author": "John Due",
    }
}

Technically, outermost dictionary of declaration is as same as inner dictionaries. So you can specify '__source_root__' the dictionary.

As list

dripper can define list of dictionaries. You need to apply '__type__': 'list'.

from dripper import dripper_factory
declaration = {
    "articles": {
        "__type__": "list",
        "__source_root__": "articles",
...
        "title": "meta1",
        "author": ["meta2", "meta22"],
    }
})
d = dripper_factory(declaration)
d({
    "articles": [
        {"meta1": "Monty Python", "meta2": {"meta22": "John Doe"}},
        {"meta1": "Flying Circus", "meta2": {"meta22": "Jane Doe"}},
    ]
}) == {
    "articles": [
        {"title": "Monty Python", "author": "John Doe"},
        {"title": "Flying Circus", "author": "Jane Doe"},
    ]
}

Advanced

Converting

Use dripper.ValueDripper to pass converter function.

import dripper
declaration = {
    "title": dripper.ValueDripper(["title"], converter=lambda s: s.lower())
}
d = dripper.dripper_factory(declaration)
d({"title": "TITLE"}) == {"title": "title"}

Technically, each ends (list) will be replaced by instance of dripper.ValueDripper.

default value

Specify default keyword argument to change default value. None will be applied as default.

import dripper
declaration = {
    "title": dripper.ValueDripper(["title"], default="default")
}
d = dripper.dripper_factory(declaration)
d({}) == {"title": "default"}

Technically, each ends (list) will be replaced by instance of dripper.ValueDripper.

Combining

By combining dripper.ValueDripper, result value of that key will be combined.

import dripper
declaration = {
    "fullname": (dripper.ValueDripper(["firstname"]) +
                 dripper.ValueDripper(["lastname"]))
}
d = dripper.dripper_factory(declaration)
d({"firstname": "Hrioki", "lastname": "Kiyohara"}) == {"fullname": "HriokiKiyohara"}

CHANGES

1.2

• Avoid deepcopy to improve speed
  • https://github.com/hirokiky/dripper/pull/6
  • Thanks @afiram

1.1

• None is default value of ValueDripper
  • Before this change ValueDripper without default keyword argument will raise DrippingError
  • In order to this behavior DictDripper will return empty dict when inner value dripper could not dig out values
  • Thanks for @bungoume to suggest this behavior

1.0

• Officially supported Python 3.5

0.3.1

• ValueDripper now accepts default argument.

0.3

• Fixed to accept string or integer directly as source_root.

0.2

• Improved error handling.
• Added MixDripper.

0.1

• Initial version