contains() [1/2]

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 the existence of an element in a JSON object given a JSON pointer

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]

ptr

JSON 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.106	if an array index begins with '0'
parse_error.109	if an array index was not a number

@complexity Logarithmic in the size of the JSON object.

@liveexample{The following code shows an example for contains().,contains_json_pointer}

See also

see contains(KeyT &&) const – checks the existence of a key

Since

version 3.7.0

Definition at line 22338 of file json.hpp.

    {
        return ptr.contains(this);
    }