What is dlist?

dlist is a pandas-like API for working with lists of dictionaries.

from dlist import dlist

# initialize from a list of dicts
dl = dlist([ { 'a': 1 }, { 'a': 2, 'b': 'cat' } ])

# positional indexing is list-like
dl[0] # {'a': 1}
dl[:2] # { 'a': 1 }, { 'a': 2, 'b': 'cat' }

# access keys as attributes or string keys
dl.a # [ 1, 2 ]
dl('a') # ditto

# make masks via all the normal operators
dl('b') == 'cat' # [ False, True ]

# caseless comparison, since that's nice
dl('b').caseless_eq('CAT') # [ False, True ]
dl('b').isin([ 1, 'CAT'], case=False) # [ False, True ]

# access things that don't exist (possibly a bad idea, but fun)
dl.c # [ None, None ]

# mildly fancy indexing
dl[dl.a >= 2] # dlist([ { 'a': 2, 'b': 'cat' } ])

# assignment from a properly-sized sequence
dl.c = [ True, set([1,2]) ] # dlist([ { 'a': 1, 'c': True }, { 'a': 2, 'b': 'cat', 'c': {1, 2} } ])

# assignment from a non-sequence
dl.d = 4 # dlist([ { 'a': 1, 'c': True, 'd': 4 }, { 'a': 2, 'b': 'cat', 'c': {1, 2}, 'd': 4 } ])

# create a new attribute
dl.e = [ '1', 2 ] # dlist([{ ..., 'e': '1' }, { ..., 'e': 2 } ]) 

# extend
dl += [ { 'f': 5 } ] # dlist([ {...}, {...}, { 'f': 5 } ]

# subtract using masks
dl -= (dl.a >= 2) 

Why didn't you just use pandas?

pandas wants to aggressively type everything. I like the flexibility of dictionaries. I suppose I could dtype=object and get most of this, but that felt icky.

Why didn't you just use <mongo/sqlite/tinydb/some-other-thing>?

Sure, something like this probably already exists. Also, maybe it's not even a good idea. But it was fun to make.