I have a list of strings, from which I have to construct a dict. So, for example, I have:
foo.bar:10
foo.hello.world:30
xyz.abc:40
pqr:100
This is represented as a dict:
{
"foo": {
"bar": 10,
"hello": {
"world": 30
}
},
"xyz": {
"abc": 40
},
"pqr": 100
}
This question is based on the same premise, but the answers discuss hardcoded depths such as:
mydict = ...
mydict['foo']['bar'] = 30
Since the dot seperated strings on the left may be of any depth, I can't figure out a way to build the dict. How should I parse the dot separated string and build the dict?
Building upon the solution in the links, you could
setdefault
lines = \
'''
foo.bar:10
foo.hello.world:30
xyz.abc:40
pqr:100
'''.splitlines()
d = {}
for l in lines:
k, v = l.split(':')
*f, l = k.split('.')
t = d
for k in f:
t = t.setdefault(k, {})
t[l] = int(v) # don't perform a conversion if your values aren't numeric
print(d)
{
"pqr": 100,
"foo": {
"bar": 10,
"hello": {
"world": 30
}
},
"xyz": {
"abc": 40
}
}
Recursive setdefault
traversal learned from here .
Breaking down each step -
Split on :
, extract the key-list string and the value
k, v = l.split(':')
Split the key-string on .
to get a list of keys. I take the opportunity to partition the keys as well, so I have a separate reference to the last key that will be the key to v
.
*f, l = k.split('.')
*f
is the catch-all assignment, and f
is a list of any number of values (possibly 0 values, if there's only one key in the key-string!)
For each key k
in the key list f
, recurse down into the "tree" using setdefault
. This is similar to recursively traversing a linked list.
for k in f: t = t.setdefault(k, {})
At the end, the last key value pair comes from l
and v
.
t[l] = v
What's wrong with incrementally building it?
mydict = {}
mydict["foo"] = {}
mydict["foo"]["bar"] = 30
mydict["foo"]["hello"] = {}
mydict["foo"]["hello"]["world"] = 30
mydict["foo"]["xyz"] = {}
mydict["foo"]["xyz"]["abc"] = 40
mydict["foo"]["pqr"] = 100
# ...
pprint.pprint(mydict) # {'foo': {'bar': 30, 'hello': {'world': 30}, 'pqr': 100, 'xyz': {'abc': 40}}}
Including the parsing, you could use something like this:
import pprint
inp = """foo.bar:10
foo.hello.world:30
xyz.abc:40
pqr:100
"""
mydict = {}
for line in inp.splitlines():
s, v = line.split(':')
parts = s.split(".")
d = mydict
for i in parts[:-1]:
if i not in d:
d[i] = {}
d = d[i]
d[parts[-1]] = v
pprint.pprint(mydict) # {'foo': {'bar': '10', 'hello': {'world': 30'}}, 'pqr': '100', 'xyz': {'abc': '40'}}
One key point to consider in your case is that you either want to create a dictionary in a parent's dictionarys value part or
an integer
x = """
foo.bar:10
foo.hello.world:30
xyz.abc:40
pqr.a:100
"""
tree = {}
for item in x.split():
level, value = item.split(":")[0], item.split(":")[1]
t = tree
for part in item.split('.'):
keyval = part.split(":")
if len(keyval) > 1:
#integer
t = t.setdefault(keyval[0], keyval[1])
else:
t = t.setdefault(part, {})
import pprint
pprint.pprint(tree)
Result:
{'foo': {'bar': '10', 'hello': {'world': '30'}},
'pqr': {'a': '100'},
'xyz': {'abc': '40'}}
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