QJsonValue¶

The QJsonValue class encapsulates a value in JSON. More…

Synopsis¶

Functions¶

def __eq__ (other)
def __ne__ (other)
def isArray ()
def isBool ()
def isDouble ()
def isNull ()
def isObject ()
def isString ()
def isUndefined ()
def operator[] (i)
def operator[] (key)
def swap (other)
def toArray ()
def toArray (defaultValue)
def toBool ([defaultValue=false])
def toDouble ([defaultValue=0])
def toInt ([defaultValue=0])
def toObject ()
def toObject (defaultValue)
def toString ()
def toString (defaultValue)
def toVariant ()
def type ()

Static functions¶

def fromVariant (variant)

Detailed Description¶

A value in JSON can be one of 6 basic types:

JSON is a format to store structured data. It has 6 basic data types:

bool Bool

double Double

string String

array Array

object Object

null Null

A value can represent any of the above data types. In addition, QJsonValue has one special flag to represent undefined values. This can be queried with isUndefined() .

The type of the value can be queried with type() or accessors like isBool() , isString() , and so on. Likewise, the value can be converted to the type stored in it using the toBool() , toString() and so on.

Values are strictly typed internally and contrary to QVariant will not attempt to do any implicit type conversions. This implies that converting to a type that is not stored in the value will return a default constructed return value.

QJsonValueRef¶

QJsonValueRef is a helper class for QJsonArray and QJsonObject . When you get an object of type QJsonValueRef , you can use it as if it were a reference to a QJsonValue . If you assign to it, the assignment will apply to the element in the QJsonArray or QJsonObject from which you got the reference.

The following methods return QJsonValueRef :

QJsonArray ::operator[](int i)

QJsonObject ::operator[](const QString & key) const

See also

JSON Support in Qt JSON Save Game Example

class QJsonValue([arg__1=Null])¶

QJsonValue(b)

QJsonValue(a)

QJsonValue(o)

QJsonValue(other)

QJsonValue(s)

QJsonValue(s)

QJsonValue(n)

QJsonValue(n)

QJsonValue(n)

param arg__1

Type

param n

double

param o

QJsonObject

param other

QJsonValue

param a

QJsonArray

param b

bool

param s

unicode

Creates a QJsonValue of type type .

The default is to create a Null value.

Creates a value of type Bool, with value b .

Creates a value of type String with value s , assuming UTF-8 encoding of the input.

You can disable this constructor by defining QT_NO_CAST_FROM_ASCII when you compile your applications.

Creates a value of type Double, with value n .

This is an overloaded function.

Creates a value of type Double, with value n .

This is an overloaded function.

Creates a value of type Double, with value n . NOTE: the integer limits for IEEE 754 double precision data is 2^53 (-9007199254740992 to +9007199254740992). If you pass in values outside this range expect a loss of precision to occur.

PySide2.QtCore.QJsonValue.Type¶

This enum describes the type of the JSON value.

Constant	Description
QJsonValue.Null	A Null value
QJsonValue.Bool	A boolean value. Use `toBool()` to convert to a bool.
QJsonValue.Double	A double. Use `toDouble()` to convert to a double.
QJsonValue.String	A string. Use `toString()` to convert to a `QString` .
QJsonValue.Array	An array. Use `toArray()` to convert to a `QJsonArray` .
QJsonValue.Object	An object. Use `toObject()` to convert to a `QJsonObject` .
QJsonValue.Undefined	The value is undefined. This is usually returned as an error condition, when trying to read an out of bounds value in an array or a non existent key in an object.

static PySide2.QtCore.QJsonValue.fromVariant(variant)¶

Parameters: variant – object
Return type: QJsonValue

Converts variant to a QJsonValue and returns it.

The conversion will convert QVariant types as follows:

QJsonValue::Map. See toJsonValue() for conversion restrictions and the “stringification” of map keys.

For all other QVariant types a conversion to a QString will be attempted. If the returned string is empty, a Null QJsonValue will be stored, otherwise a String value using the returned QString .

See also

toVariant()

PySide2.QtCore.QJsonValue.isArray()¶

Return type: bool

Returns true if the value contains an array.

See also

toArray()

PySide2.QtCore.QJsonValue.isBool()¶

Return type: bool

Returns true if the value contains a boolean.

See also

toBool()

PySide2.QtCore.QJsonValue.isDouble()¶

Return type: bool

Returns true if the value contains a double.

See also

toDouble()

PySide2.QtCore.QJsonValue.isNull()¶

Return type: bool

Returns true if the value is null.

PySide2.QtCore.QJsonValue.isObject()¶

Return type: bool

Returns true if the value contains an object.

See also

toObject()

PySide2.QtCore.QJsonValue.isString()¶

Return type: bool

Returns true if the value contains a string.

See also

toString()

PySide2.QtCore.QJsonValue.isUndefined()¶

Return type: bool

Returns true if the value is undefined. This can happen in certain error cases as e.g. accessing a non existing key in a QJsonObject .

PySide2.QtCore.QJsonValue.__ne__(other)¶

Parameters: other – QJsonValue
Return type: bool

Returns true if the value is not equal to other .

PySide2.QtCore.QJsonValue.__eq__(other)¶

Parameters: other – QJsonValue
Return type: bool

Returns true if the value is equal to other .

PySide2.QtCore.QJsonValue.operator[](key)

Parameters: key – unicode
Return type: QJsonValue

PySide2.QtCore.QJsonValue.operator[](i)

Parameters: i – int
Return type: QJsonValue

Returns a QJsonValue representing the value for index i .

Equivalent to calling toArray() .at(i).

The returned QJsonValue is Undefined , if i is out of bounds, or if isArray() is false.

PySide2.QtCore.QJsonValue.swap(other)¶

Parameters: other – QJsonValue

Swaps the value other with this. This operation is very fast and never fails.

PySide2.QtCore.QJsonValue.toArray()¶

Return type: QJsonArray

This is an overloaded function.

Converts the value to an array and returns it.

If type() is not Array, a QJsonArray() will be returned.

PySide2.QtCore.QJsonValue.toArray(defaultValue)

Parameters: defaultValue – QJsonArray
Return type: QJsonArray

Converts the value to an array and returns it.

If type() is not Array, the defaultValue will be returned.

PySide2.QtCore.QJsonValue.toBool([defaultValue=false])¶

Parameters: defaultValue – bool
Return type: bool

Converts the value to a bool and returns it.

If type() is not bool, the defaultValue will be returned.

PySide2.QtCore.QJsonValue.toDouble([defaultValue=0])¶

Parameters: defaultValue – double
Return type: double

Converts the value to a double and returns it.

If type() is not Double, the defaultValue will be returned.

PySide2.QtCore.QJsonValue.toInt([defaultValue=0])¶

Parameters: defaultValue – int
Return type: int

Converts the value to an int and returns it.

If type() is not Double or the value is not a whole number, the defaultValue will be returned.

PySide2.QtCore.QJsonValue.toObject()¶

Return type: QJsonObject

This is an overloaded function.

Converts the value to an object and returns it.

If type() is not Object, the QJsonObject() will be returned.

PySide2.QtCore.QJsonValue.toObject(defaultValue)

Parameters: defaultValue – QJsonObject
Return type: QJsonObject

Converts the value to an object and returns it.

If type() is not Object, the defaultValue will be returned.

PySide2.QtCore.QJsonValue.toString()¶

Return type: unicode

Converts the value to a QString and returns it.

If type() is not String, a null QString will be returned.

See also

isNull()

PySide2.QtCore.QJsonValue.toString(defaultValue)

Parameters: defaultValue – unicode
Return type: unicode

Converts the value to a QString and returns it.

If type() is not String, the defaultValue will be returned.

PySide2.QtCore.QJsonValue.toVariant()¶

Return type: object

Converts the value to a QVariant() .

The QJsonValue types will be converted as follows:

Null
Nullptr

See also

fromVariant()

PySide2.QtCore.QJsonValue.type()¶

Return type: Type

Returns the type of the value.

See also

Type

Qt Documentation

Table of Contents

QJsonValue¶

Synopsis¶

Functions¶

Static functions¶

Detailed Description¶

QJsonValueRef¶