I'm trying to create a recursive function that takes a JSON dictionary and stores any value with key names 'rate' into a list. I will then take that list and find the lowest value. My code looks like this right now, but is producing multiple empty lists within the list.
def recurse_keys(df):
rates = []
for key, value in df.items():
if key == 'rate':
rates.append(value)
if isinstance(df[key], dict):
recurse_keys(df[key])
You need to combine the results from the recursion, and return it:
def recurse_keys(df):
rates = []
for key, value in df.items():
if key == 'rate':
rates.append(value)
if isinstance(df[key], dict):
rates += recurse_keys(df[key])
return rates
df[key] and value are the same, no? Is there a reason to mix?rates)? This method would seem less intuitive, but maybe I'm wrong?
Code:
def recurse_keys(df):
rates = []
for key, value in df.items():
if key == 'rate':
rates.append(value)
if isinstance(df[key], dict):
rates += recurse_keys(df[key])
return rates
You can also initialize the rates list outside of the recursive function and pass it to the function, as list is a mutable datastructure, it'll be passed as reference. Like this (not tested though):
def recurse_keys(df, rates):
for key, value in df.items():
if key == 'rate':
rates.append(value)
if isinstance(df[key], dict):
recurse_keys(df[key], rates)
def calling_method():
rates = []
recurse_keys(df, rates)
you need pass rates as rates, it seems in every recursion you do create new rates list.
def recurse_keys(df, rates=[]):
for key, value in df.items():
if key == 'rate':
rates.append(value)
if isinstance(df[key], dict):
recurse_keys(df[key], rates)
return rates
result = recurse_keys(df)
min(result)
recurse_keys(df[key]) instead of recurse_keys(df[key], rates) would still work, but only the first time it is called.
rates = []on each recursive call.recurse_keys, it's creating a newrateslist which is initially empty. Presumably this is not what you want.