ArduinoJson: API Reference

JsonVariant::as()

Description

Get the value of the specified type.

Signatures
bool               as<bool>() const;

float              as<float>() const;
double             as<double>() const;

signed char        as<signed char>() const;
unsigned char      as<unsigned char>() const;
signed int         as<signed int>() const;
unsigned int       as<unsigned int>() const;
signed short       as<signed short>() const;
unsigned short     as<unsigned short>() const;
signed long        as<signed long>() const;
unsigned long      as<unsigned long>() const;
unsigned long long as<unsigned long long>() const;   // <- may require ARDUINOJSON_USE_LONG_LONG
signed long long   as<signed long long>() const;     // <- may require ARDUINOJSON_USE_LONG_LONG
signed __int64     as<signed __int64>() const;       // <- may require ARDUINOJSON_USE_INT64
unsigned __int64   as<unsigned __int64>() const;     // <- may require ARDUINOJSON_USE_INT64

const char*        as<char*>() const;
const char*        as<const char*>() const;
String             as<String>() const;               // <- causes duplication of the string
std::string        as<std::string>() const;          // <- causes duplication of the string

JsonArray&         as<JsonArray>() const;
JsonArray&         as<JsonArray&>() const;
JsonArray&         as<const JsonArray&>() const;
JsonObject&        as<JsonObject>() const;
JsonObject&        as<JsonObject&>() const;
JsonObject&        as<const JsonObject&>() const;
Return value

The value of the specified type or a default value if the JsonVariant is not compatible with the specified type.

The default value is:

  • 0 for numerical types
  • NULL for const char*
  • JsonArray::invalid() for JsonArray&
  • JsonObject::invalid() for JsonObject&
Example
JsonVariant variant = 42;
int i = variant.as<int>(); // <- i == 42
double d = variant.as<double>(); // <- d == 42.0
const char* s = variant.as<char*>(); // <- s == NULL
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