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2f087c6b73
- API pages for operator[], at, front, back, find, contains, count, begin, end, cbegin, cend, items, and type_name of basic_json_view, linked both ways with the basic_json pages - the feature page and size() describe document order and duplicate keys - the examples show when the view helps: reading a few fields of a large text, probing optional members, and members in source order Signed-off-by: Niels Lohmann <mail@nlohmann.me>
30 lines
829 B
C++
30 lines
829 B
C++
#include <iostream>
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#include <nlohmann/json_view.hpp>
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using json_document = nlohmann::json_document;
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int main()
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{
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// a batch of incoming events; only some carry a "user_id" -- find()
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// locates it without throwing for the events that turn out to not be
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// objects, and without materializing an event that does not match
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json_document batch = json_document::parse(R"(
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[
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{"type": "click", "user_id": 42},
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{"type": "ping"},
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{"type": "click", "user_id": 7}
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]
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)");
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const auto events = batch.root();
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for (std::size_t i = 0; i < events.size(); ++i)
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{
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const auto event = events[i];
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const auto it = event.find("user_id");
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if (it != event.end())
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{
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std::cout << "user " << it->materialize().dump() << '\n';
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}
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}
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}
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