Let us select dict values by criteria on their associated keys #20
Comments
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I like it. Having a built in function for this would be really useful. I've also seen requests for the opposite case: going from a list of key/val mappings back to a hash, so having a pair of functions that could convert to/from both forms would be really helpful. |
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I'm also interested in this. How about the following set of functions:
I implemented these for myself using the import jmespath
from jmespath import functions
from jmespath.compat import iteritems
from jmespath.compat import map
class CustomFunctions(functions.Functions):
@functions.signature({'types': ['object']})
def _func_items(self, arg):
return list(map(list, iteritems(arg)))
@functions.signature({'types': ['array'], 'variadic': True})
def _func_zip(self, *arguments):
return list(map(list, zip(*arguments)))
@functions.signature({'types': ['array']})
def _func_to_object(self, pairs):
return dict(pairs)
subject = {
'keys': [
u'One',
u'Two',
u'Three',
u'Four'
],
'values': [
1,
2,
3,
4
]
}
options = jmespath.Options(custom_functions=CustomFunctions())
# prints {u'Four': 4, u'Three': 3, u'Two': 2, u'One': 1}
mapped = jmespath.search('to_object(zip(keys, values))', subject, options=options)
print(mapped)
# prints {u'Three': 3, u'Two': 2}
print(
jmespath.search(
'items(@) | [?starts_with([0], `T`)] | to_object(@)', mapped, options=options)
)I would be happy to add tests for these and submit a PR for the python implementation. |
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I like it. I think this is a good balance between ease of use/familiarity as well as exposing useful low level primitives that you can build on. 👍 from me. @jmespath/dev any concerns? |
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👍 from me |
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👍 from me too. |
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Renamed |
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4 years old issue.. why taking so much? |
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Friendly ping! |
Let's say I have
{ 'bark': 'oink', 'foo1': 'foo', 'foo2': 'woof', 'foo3': 'meow' }and want to select all values for which keys start with "foo". I tried for a bit to get JMESPath to get me
['foo', 'woof', 'meow']but was unsuccessful. I don't know if it's impossible, but I was thinking that a simple approach might be a built-in function calledpivot/reify/mappings(I'm bad at naming) that transforms the above into a list of Key/Value mappings, so:[ { 'Key': 'bark', 'Value': 'oink' }, { 'Key': 'foo1', 'Value': 'foo' }, { 'Key': 'foo2', 'Value': 'woof' }, { 'Key': 'foo3', 'Value': 'meow' } ]which seems far easier to deal with. I'm open to other approaches to achieving the same goal, of course 😄
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