How to read from a JSON with two keys - json

Question

I have a json that I need to import and then return a certain value. The json has two keys, like
{
"NUM_High_Objects": {
"abseta_pt": {
"field1:[0.0,0.9]": {
"field2:[15,20]": {
"tagIso": 0.00012,
"value": 0.99
},
"field2:[20,25]": {
"tagIso": 0.00035,
"value": 0.98
}
},
"field1:[0.91,1.2]": {
"field2:[15,20]": {
"tagIso": 0.00013,
"value": 0.991
},
"field2:[20,25]": {
"tagIso": 0.00036,
"value": 0.975
}
},
"binning": [
{
"binning": [
0.0,
0.9,
1.2,
2.1,
2.4
],
"variable": "abseta"
},
{
"binning": [
15,
20,
25,
30,
40,
50,
60,
120
],
"variable": "pt"
}
]
}
},
What I need is to search if a pair of values is within the range of "field1" and "field2" and return the corresponding "value"
I tried following this Search nested json / dict for multiple key values matching specified keys but could not make it to work...
I ve tried something like
class checkJSON() :
def __init__(self,filein) :
self.good, self.bad = 0, 0
print 'inside json function : will use the JSON', filein
input_file = open (filein)
self.json_array = json.load(input_file)
def checkJSON(self,LS,run) :
try :
LSlist = self.json_array[str(run)]
for LSrange in LSlist :print LSrange, run
except KeyError :
pass
self.bad += 1
return False
CJ=''
CJ=checkJSON(filein='test.json')
isInJSON = CJ.checkJSON("0.5", "20")
print isInJSON
but this does not work as I am not sure how to loop inside the keys

Answer 1

If I am understanding your question correctly then the relevant portion of your JSON is:
{
"field1:[0.0,0.9]": {
"field2:[15,20]": {
"tagIso": 0.00012,
"value": 0.99
},
"field2:[20,25]": {
"tagIso": 0.00035,
"value": 0.98
}
},
"field1:[0.91,1.2]": {
"field2:[15,20]": {
"tagIso": 0.00013,
"value": 0.991
},
"field2:[20,25]": {
"tagIso": 0.00036,
"value": 0.975
}
},
"binning": [
{
"binning": [
0.0,
0.9,
1.2,
2.1,
2.4
],
"variable": "abseta"
},
{
"binning": [
15,
20,
25,
30,
40,
50,
60,
120
],
"variable": "pt"
}
]
}
Then the following code should do what you are trying to achieve. It doesn't look like you need to search for nested keys, you simply need to parse your field1[...] and field2[...]. The code below is a quick implementation of what I understand you are trying to achieve. It will return the value if the first parameter is in the range of a field1[...] and the second parameter is in the range of a field2[...]. Otherwise, it will return None.
import json
def check_json(jsondict, l1val, l2val):
def parse_key(keystr):
level, lrange = keystr.split(':')
return level, eval(lrange)
for l1key, l2dict in jsondict.items():
if 'field' in l1key:
l1, l1range = parse_key(l1key)
if l1val >= l1range[0] and l1val <= l1range[1]:
for l2key, vals in l2dict.items():
l2, l2range = parse_key(l2key)
if l2val >= l2range[0] and l2val <= l2range[1]:
return vals['value']
return None
Here is a driver code to test the implementation above.
if __name__ == '__main__':
with open('data.json', 'r') as f:
myjson = json.load(f)
print(check_json(myjson, 0.5, 20))