JSON for Modern C++  3.9.1

◆ contains() [2/2]

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 = std::int64_t, class NumberUnsignedType = std::uint64_t, class NumberFloatType = double, template< typename U > class AllocatorType = std::allocator, template< typename T, typename SFINAE=void > class JSONSerializer = adl_serializer, class BinaryType = std::vector<std::uint8_t>>
bool nlohmann::basic_json< ObjectType, ArrayType, StringType, BooleanType, NumberIntegerType, NumberUnsignedType, NumberFloatType, AllocatorType, JSONSerializer, BinaryType >::contains ( const json_pointer &  ptr) const
inline

Check whether the given JSON pointer ptr can be resolved in the current JSON value.

Note
This method can be executed on any JSON value type.
Parameters
[in]ptrJSON pointer to check its existence.
Returns
true if the JSON pointer can be resolved to a stored value, false otherwise.
Postcondition
If j.contains(ptr) returns true, it is safe to call j[ptr].
Exceptions
parse_error.106if an array index begins with '0'
parse_error.109if an array index was not a number
Complexity^^ Logarithmic in the size of the JSON object.
Example^^ The following code shows an example for contains(). ^^ contains_json_pointer.cpp
Output (play with this example online):^^
true
true
true
true
false
false
false
^^ The example code above can be translated with
g++ -std=c++11 -Isingle_include doc/examples/contains_json_pointer.cpp -o contains_json_pointer 
See also
contains(KeyT &&) const – checks the existence of a key
Since
version 3.7.0

Definition at line 20937 of file json.hpp.