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Extended JSON parsing
Apparently .j.k loses precision with large enough numbers:
q)`long$.j.k"1471220573128024107" 1471220573128024064
However I’m trying to interface with a program that expects the number to round-trip, i.e. if I export the JSON again, it should contain exactly 1471220573128024107, so I can’t use .j.k to import the file as it loses precision. There are parsers for other languages that can convert to long integers when a number is encountered and only force a conversion to float when there is a decimal point or exponent in the JSON.
Is there any existing library that can do the same for q?
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1 Reply
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A user has written qrapidjson which implements .j.j but not .j.k
The underlying rapidjson library does allow a parse flag kParseNumbersAsStringsFlag
http://rapidjson.org/namespacerapidjson.html#a81379eb4e94a0386d71d15fda882ebc9
Although in a quick test the library looks to already parse numbers without decimal places as longs by default:
q)rapidjson:.p.import`rapidjson
q)rapidjson[`:loads]["1471220573128024107"]` 1471220573128024107
q)type rapidjson[`:loads]["1471220573128024107"]` -7h
q)type each rapidjson[`:loads]["[1471220573128024107, 1471220573128024107.0]"]` -7 -9h //Same for default json library in python
q)json:.p.import`json
q)json[`:loads]["1471220573128024107"]` 1471220573128024107
q)type json[`:loads]["1471220573128024107"]` -7h
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