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template< template< typename U, typename V, typename...Args > class ObjectType = std::map, template< typename U, typename...Args > class ArrayType = std::vector, class StringType = std::string, class BooleanType = bool, class NumberIntegerType = int64_t, class NumberFloatType = double, template< typename U > class AllocatorType = std::allocator> < / div >
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< td class = "memname" > < a class = "el" href = "classnlohmann_1_1basic__json_a80ceaa3bdd346292273b309e08525c1c.html#a80ceaa3bdd346292273b309e08525c1c" > size_type< / a > < a class = "el" href = "classnlohmann_1_1basic__json.html" > nlohmann::basic_json< / a > ::size < / td >
< td > (< / td >
< td class = "paramname" > < / td > < td > )< / td >
< td > const< / td >
< / tr >
< / table >
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< p > Returns the number of elements in a JSON value.< / p >
< dl class = "section return" > < dt > Returns< / dt > < dd > The return value depends on the different value types and is defined as follows: < table class = "doxtable" >
< tr >
< th > Value type < / th > < th > return value < / th > < / tr >
< tr >
< td > null < / td > < td > < code > 0< / code > < / td > < / tr >
< tr >
< td > boolean < / td > < td > < code > 1< / code > < / td > < / tr >
< tr >
< td > string < / td > < td > < code > 1< / code > < / td > < / tr >
< tr >
< td > number < / td > < td > < code > 1< / code > < / td > < / tr >
< tr >
< td > object < / td > < td > result of function object_t::size() < / td > < / tr >
< tr >
< td > array < / td > < td > result of function array_t::size() < / td > < / tr >
< / table >
< / dd > < / dl >
< dl class = "section user" > < dt > Complexity< / dt > < dd > Constant, as long as < a class = "el" href = "classnlohmann_1_1basic__json_ac82abedf356d252e0589850c3d8b35ba.html#ac82abedf356d252e0589850c3d8b35ba" > array_t< / a > and < a class = "el" href = "classnlohmann_1_1basic__json_a63691315292df8e1522b00d37ebb1ffc.html#a63691315292df8e1522b00d37ebb1ffc" > object_t< / a > satisfy the Container concept; that is, their < a class = "el" href = "classnlohmann_1_1basic__json_af49c37bbda87f36170c67f960db3781a.html#af49c37bbda87f36170c67f960db3781a" title = "returns the number of elements " > size()< / a > functions have constant complexity.< / dd > < / dl >
< dl class = "section user" > < dt > Requirements< / dt > < dd > This function satisfies the Container requirements:< ul >
< li > The complexity is constant.< / li >
< li > Has the semantics of < code > std::distance(< a class = "el" href = "classnlohmann_1_1basic__json_af4261341695729a8e657b94772f95516.html#af4261341695729a8e657b94772f95516" title = "returns an iterator to the first element " > begin()< / a > , < a class = "el" href = "classnlohmann_1_1basic__json_ad8f84e6fb9bbf9a7bc767962ad0fe3a1.html#ad8f84e6fb9bbf9a7bc767962ad0fe3a1" title = "returns an iterator to one past the last element " > end()< / a > )< / code > .< / li >
< / ul >
< / dd > < / dl >
< dl class = "section user" > < dt > Example< / dt > < dd > The following code calls < a class = "el" href = "classnlohmann_1_1basic__json_af49c37bbda87f36170c67f960db3781a.html#af49c37bbda87f36170c67f960db3781a" > size< / a > on the different value types. < div class = "fragment" > < div class = "line" > < a name = "l00001" > < / a > < span class = "lineno" > 1< / span >   < span class = "preprocessor" > #include < json.hpp> < / span > < / div >
< div class = "line" > < a name = "l00002" > < / a > < span class = "lineno" > 2< / span >   < / div >
< div class = "line" > < a name = "l00003" > < / a > < span class = "lineno" > 3< / span >   < span class = "keyword" > using namespace < / span > < a class = "code" href = "namespacenlohmann.html" > nlohmann< / a > ;< / div >
< div class = "line" > < a name = "l00004" > < / a > < span class = "lineno" > 4< / span >   < / div >
< div class = "line" > < a name = "l00005" > < / a > < span class = "lineno" > 5< / span >   < span class = "keywordtype" > int< / span > main()< / div >
< div class = "line" > < a name = "l00006" > < / a > < span class = "lineno" > 6< / span >   {< / div >
< div class = "line" > < a name = "l00007" > < / a > < span class = "lineno" > 7< / span >   < span class = "comment" > // create JSON values< / span > < / div >
< div class = "line" > < a name = "l00008" > < / a > < span class = "lineno" > 8< / span >   < a class = "code" href = "classnlohmann_1_1basic__json.html" > json< / a > j_null;< / div >
< div class = "line" > < a name = "l00009" > < / a > < span class = "lineno" > 9< / span >   < a class = "code" href = "classnlohmann_1_1basic__json.html" > json< / a > j_boolean = < span class = "keyword" > true< / span > ;< / div >
< div class = "line" > < a name = "l00010" > < / a > < span class = "lineno" > 10< / span >   < a class = "code" href = "classnlohmann_1_1basic__json.html" > json< / a > j_number_integer = 17;< / div >
< div class = "line" > < a name = "l00011" > < / a > < span class = "lineno" > 11< / span >   < a class = "code" href = "classnlohmann_1_1basic__json.html" > json< / a > j_number_float = 23.42;< / div >
< div class = "line" > < a name = "l00012" > < / a > < span class = "lineno" > 12< / span >   < a class = "code" href = "classnlohmann_1_1basic__json.html" > json< / a > j_object = {{< span class = "stringliteral" > " one" < / span > , 1}, {< span class = "stringliteral" > " two" < / span > , 2}};< / div >
< div class = "line" > < a name = "l00013" > < / a > < span class = "lineno" > 13< / span >   < a class = "code" href = "classnlohmann_1_1basic__json.html" > json< / a > j_object_empty(< a class = "code" href = "classnlohmann_1_1basic__json_a231b02148577b69a154b2ce2c87a5522.html#a231b02148577b69a154b2ce2c87a5522aa8cfde6331bd59eb2ac96f8911c4b666" > json::value_t::object< / a > );< / div >
< div class = "line" > < a name = "l00014" > < / a > < span class = "lineno" > 14< / span >   < a class = "code" href = "classnlohmann_1_1basic__json.html" > json< / a > j_array = {1, 2, 4, 8, 16};< / div >
< div class = "line" > < a name = "l00015" > < / a > < span class = "lineno" > 15< / span >   < a class = "code" href = "classnlohmann_1_1basic__json.html" > json< / a > j_array_empty(< a class = "code" href = "classnlohmann_1_1basic__json_a231b02148577b69a154b2ce2c87a5522.html#a231b02148577b69a154b2ce2c87a5522af1f713c9e000f5d3f280adbd124df4f5" > json::value_t::array< / a > );< / div >
< div class = "line" > < a name = "l00016" > < / a > < span class = "lineno" > 16< / span >   < a class = "code" href = "classnlohmann_1_1basic__json.html" > json< / a > j_string = < span class = "stringliteral" > " Hello, world" < / span > ;< / div >
< div class = "line" > < a name = "l00017" > < / a > < span class = "lineno" > 17< / span >   < / div >
< div class = "line" > < a name = "l00018" > < / a > < span class = "lineno" > 18< / span >   < span class = "comment" > // call size()< / span > < / div >
< div class = "line" > < a name = "l00019" > < / a > < span class = "lineno" > 19< / span >   std::cout < < j_null.< a class = "code" href = "classnlohmann_1_1basic__json_af49c37bbda87f36170c67f960db3781a.html#af49c37bbda87f36170c67f960db3781a" > size< / a > () < < < span class = "charliteral" > ' \n' < / span > ;< / div >
< div class = "line" > < a name = "l00020" > < / a > < span class = "lineno" > 20< / span >   std::cout < < j_boolean.< a class = "code" href = "classnlohmann_1_1basic__json_af49c37bbda87f36170c67f960db3781a.html#af49c37bbda87f36170c67f960db3781a" > size< / a > () < < < span class = "charliteral" > ' \n' < / span > ;< / div >
< div class = "line" > < a name = "l00021" > < / a > < span class = "lineno" > 21< / span >   std::cout < < j_number_integer.< a class = "code" href = "classnlohmann_1_1basic__json_af49c37bbda87f36170c67f960db3781a.html#af49c37bbda87f36170c67f960db3781a" > size< / a > () < < < span class = "charliteral" > ' \n' < / span > ;< / div >
< div class = "line" > < a name = "l00022" > < / a > < span class = "lineno" > 22< / span >   std::cout < < j_number_float.< a class = "code" href = "classnlohmann_1_1basic__json_af49c37bbda87f36170c67f960db3781a.html#af49c37bbda87f36170c67f960db3781a" > size< / a > () < < < span class = "charliteral" > ' \n' < / span > ;< / div >
< div class = "line" > < a name = "l00023" > < / a > < span class = "lineno" > 23< / span >   std::cout < < j_object.< a class = "code" href = "classnlohmann_1_1basic__json_af49c37bbda87f36170c67f960db3781a.html#af49c37bbda87f36170c67f960db3781a" > size< / a > () < < < span class = "charliteral" > ' \n' < / span > ;< / div >
< div class = "line" > < a name = "l00024" > < / a > < span class = "lineno" > 24< / span >   std::cout < < j_object_empty.size() < < < span class = "charliteral" > ' \n' < / span > ;< / div >
< div class = "line" > < a name = "l00025" > < / a > < span class = "lineno" > 25< / span >   std::cout < < j_array.< a class = "code" href = "classnlohmann_1_1basic__json_af49c37bbda87f36170c67f960db3781a.html#af49c37bbda87f36170c67f960db3781a" > size< / a > () < < < span class = "charliteral" > ' \n' < / span > ;< / div >
< div class = "line" > < a name = "l00026" > < / a > < span class = "lineno" > 26< / span >   std::cout < < j_array_empty.size() < < < span class = "charliteral" > ' \n' < / span > ;< / div >
< div class = "line" > < a name = "l00027" > < / a > < span class = "lineno" > 27< / span >   std::cout < < j_string.< a class = "code" href = "classnlohmann_1_1basic__json_af49c37bbda87f36170c67f960db3781a.html#af49c37bbda87f36170c67f960db3781a" > size< / a > () < < < span class = "charliteral" > ' \n' < / span > ;< / div >
< div class = "line" > < a name = "l00028" > < / a > < span class = "lineno" > 28< / span >   }< / div >
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< div class = "ttc" id = "classnlohmann_1_1basic__json_html" > < div class = "ttname" > < a href = "classnlohmann_1_1basic__json.html" > nlohmann::basic_json< / a > < / div > < div class = "ttdoc" > a class to store JSON values < / div > < div class = "ttdef" > < b > Definition:< / b > json.hpp:121< / div > < / div >
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< div class = "ttc" id = "classnlohmann_1_1basic__json_a231b02148577b69a154b2ce2c87a5522_html_a231b02148577b69a154b2ce2c87a5522aa8cfde6331bd59eb2ac96f8911c4b666" > < div class = "ttname" > < a href = "classnlohmann_1_1basic__json_a231b02148577b69a154b2ce2c87a5522.html#a231b02148577b69a154b2ce2c87a5522aa8cfde6331bd59eb2ac96f8911c4b666" > nlohmann::basic_json::value_t::object< / a > < / div > < div class = "ttdoc" > object (unordered set of name/value pairs) < / div > < / div >
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< div class = "ttc" id = "namespacenlohmann_html" > < div class = "ttname" > < a href = "namespacenlohmann.html" > nlohmann< / a > < / div > < div class = "ttdoc" > namespace for Niels Lohmann < / div > < div class = "ttdef" > < b > Definition:< / b > json.hpp:56< / div > < / div >
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< div class = "ttc" id = "classnlohmann_1_1basic__json_a231b02148577b69a154b2ce2c87a5522_html_a231b02148577b69a154b2ce2c87a5522af1f713c9e000f5d3f280adbd124df4f5" > < div class = "ttname" > < a href = "classnlohmann_1_1basic__json_a231b02148577b69a154b2ce2c87a5522.html#a231b02148577b69a154b2ce2c87a5522af1f713c9e000f5d3f280adbd124df4f5" > nlohmann::basic_json::value_t::array< / a > < / div > < div class = "ttdoc" > array (ordered collection of values) < / div > < / div >
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< div class = "ttc" id = "classnlohmann_1_1basic__json_af49c37bbda87f36170c67f960db3781a_html_af49c37bbda87f36170c67f960db3781a" > < div class = "ttname" > < a href = "classnlohmann_1_1basic__json_af49c37bbda87f36170c67f960db3781a.html#af49c37bbda87f36170c67f960db3781a" > nlohmann::basic_json::size< / a > < / div > < div class = "ttdeci" > size_type size() const noexcept< / div > < div class = "ttdoc" > returns the number of elements < / div > < div class = "ttdef" > < b > Definition:< / b > json.hpp:2501< / div > < / div >
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< / div > <!-- fragment --> Output: < pre class = "fragment" > 0
1
1
1
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0
5
0
1
< / pre > The example code above can be translated with< pre class = "fragment" > g++ -std=c++11 -Isrc doc/examples/size.cpp -o size < / pre > . < / dd > < / dl >
< / div >
< / div >
< / div > <!-- contents -->
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< li class = "navelem" > < a class = "el" href = "namespacenlohmann.html" > nlohmann< / a > < / li > < li class = "navelem" > < a class = "el" href = "classnlohmann_1_1basic__json.html" > basic_json< / a > < / li >
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< li class = "footer" > Generated on Mon Jun 22 2015 23:21:59 for JSON for Modern C++ by
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