The problem
I would like to create a dictionary of dicts out of a flat list I have in order to add a "sequentiality" piece of information, but I am having some trouble finding a solution.
The list is something like
a = ['Q=123', 'W=456', 'E=789', 'Q=753', 'W=159', 'E=888']
and I am shooting for a dict
like:
dictionary = {
'Step_1': {
'Q=123',
'W=456',
'E=789'
},
'Step_2': {
'Q=753',
'W=159',
'E=888'
}
}
I would like to end up with a function with an arbitrary number of Steps
, in order to apply it to my dataset. Suppose that in the dataset there are lists like a
with 1 <= n <6 Steps
each.
My idea
Up to now, I came up with this:
nsteps = a.count("Q")
data = {}
for i in range(nsteps):
stepi = {}
for element in a:
new = element.split("=")
if new[0] not in stepi:
stepi[new[0]] = new[1]
else:
pass
data[f"Step_{i}"] = stepi
but it doesn't work as intended: both steps in the final dictionary contain the data of Step_1
.
Any idea on how to solve this?
CodePudding user response:
One way would be:
a = ['Q=123', 'W=456', 'E=789', 'Q=753', 'W=159', 'E=888']
indices = [i for i, v in enumerate(a) if v[0:2] == 'Q=']
dictionary = {f'Step_{idx 1}': {k: v for k, v in (el.split('=') for el in a[s:e])}
for idx, (s, e) in enumerate(zip(indices, indices[1:] [len(a)]))}
print(dictionary)
{'Step_1': {'Q': '123', 'W': '456', 'E': '789'},
'Step_2': {'Q': '753', 'W': '159', 'E': '888'}}
Details:
a = ['Q=123', 'W=456', 'E=789', 'Q=753', 'W=159', 'E=888']
# Get indices where a step starts.
# This could handle also steps with variable amount of elements and keys starting with 'Q' that are not exactly 'Q'.
indices = [i for i, v in enumerate(a) if v[0:2] == 'Q=']
# Get the slices of the list starting at Q and ending before the next Q.
slices = list(zip(indices, indices[1:] [len(a)]))
print(slices)
# [(0, 3), (3, 6)]
# Get step index and (start, end) pair for each slice.
idx_slices = list(enumerate(slices))
print(idx_slices)
# [(0, (0, 3)), (1, (3, 6))]
# Split the strings in the list slices and use the result as key-value pair for a given start:end.
# Here an example for step 1:
step1 = idx_slices[0][1] # This is (0, 3).
dict_step1 = {k: v for k, v in (el.split('=') for el in a[step1[0]:step1[1]])}
print(dict_step1)
# {'Q': '123', 'W': '456', 'E': '789'}
# Do the same for each slice.
step_dicts = {f'Step_{idx 1}': {k: v for k, v in (el.split('=') for el in a[s:e])}
for idx, (s, e) in idx_slices}
print(step_dicts)
# {'Step_1': {'Q': '123', 'W': '456', 'E': '789'}, 'Step_2': {'Q': '753', 'W': '159', 'E': '888'}}
CodePudding user response:
You were almost there. The way you were counting the number of "Q"s was wrong and some lines of code had a wrong indentation (for instance data[f"Step_{i}"] = stepi
)
a = ['Q=123', 'W=456', 'E=789', 'Q=753', 'W=159', 'E=888']
def main():
nsteps = len([s for s in a if "Q" in s])
data = {}
for i in range(nsteps):
stepi = {}
for element in a:
new = element.split("=")
if new[0] not in stepi:
stepi[new[0]] = new[1]
data[f"Step_{i}"] = stepi
return data
if __name__ == "__main__":
data = main()
CodePudding user response:
First group by items like this:
a = ['Q=123', 'W=456', 'E=789', 'Q=753', 'W=159', 'E=888']
o = groupby(sorted(a, key=lambda x: x[0]), key=lambda x: x[0])
then create a dictionary like this:
d = {i: [j[1] for j in g] for i, g in o}
then iterate over them and make your result:
result = {f"step_{i 1}": [v[i] for v in r.items()] for i in range(len(max(r.values(), key=len)))}
the result will be:
Out[47]: {'step_1': ['E=789', 'Q=123', 'W=456'], 'step_2': ['E=888', 'Q=753', 'W=159']}
CodePudding user response:
From what I understood from your question:
We can group the items in the list, in this case, a group of three elements, and loop through them three at a time.
With some help from this answer:
from itertools import zip_longest
a = ['Q=123', 'W=456', 'E=789', 'Q=753', 'W=159', 'E=888']
def grouper(n, iterable):
args = [iter(iterable)] * n
return zip_longest(*args)
result = dict()
for i, d in enumerate(grouper(3, a), start=1):
dict.update({f"Step_{i}": set(d)})
print(result)
{
'Step_1': {'E=789', 'Q=123', 'W=456'},
'Step_2': {'E=888', 'Q=753', 'W=159'}
}