QJsonValue ¶

QJsonValue class encapsulates a value in JSON. 更多 …

概要 ¶

函数 ¶

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 ()

静态函数 ¶

def fromVariant (variant)

详细描述 ¶

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

JSON 是结构化数据存储格式。它有 6 种基本数据类型：

bool Bool

double Double

string 字符串

array 数组

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

另请参阅

在 Qt 中支持 JSON JSON 保存游戏范例

class QJsonValue ( [ arg__1=Null ] ) ¶

QJsonValue(b)

QJsonValue(a)

QJsonValue(o)

QJsonValue(other)

QJsonValue(s)

QJsonValue(s)

QJsonValue(n)

QJsonValue(n)

QJsonValue(v)

param arg__1

Type

param n

double

param o

QJsonObject

param other

QJsonValue

param a

QJsonArray

param b

bool

param s

unicode

param v

qint64

创建 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 v .

这是重载函数。

Creates a value of type Double, with value v .

这是重载函数。

Creates a value of type Double, with value v . 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.

常量	描述
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 ) ¶

参数: variant – object
返回类型: QJsonValue

转换 variant 到 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 .

另请参阅

toVariant()

PySide2.QtCore.QJsonValue. isArray ( ) ¶

返回类型: bool

返回 true if the value contains an array.

另请参阅

toArray()

PySide2.QtCore.QJsonValue. isBool ( ) ¶

返回类型: bool

返回 true if the value contains a boolean.

另请参阅

toBool()

PySide2.QtCore.QJsonValue. isDouble ( ) ¶

返回类型: bool

返回 true if the value contains a double.

另请参阅

toDouble()

PySide2.QtCore.QJsonValue. isNull ( ) ¶

返回类型: bool

返回 true if the value is null.

PySide2.QtCore.QJsonValue. isObject ( ) ¶

返回类型: bool

返回 true if the value contains an object.

另请参阅

toObject()

PySide2.QtCore.QJsonValue. isString ( ) ¶

返回类型: bool

返回 true if the value contains a string.

另请参阅

toString()

PySide2.QtCore.QJsonValue. isUndefined ( ) ¶

返回类型: bool

返回 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 ) ¶

参数: other – QJsonValue
返回类型: bool

返回 true if the value is not equal to other .

PySide2.QtCore.QJsonValue. __eq__ ( other ) ¶

参数: other – QJsonValue
返回类型: bool

返回 true if the value is equal to other .

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

参数: key – unicode
返回类型: QJsonValue

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

参数: i – int
返回类型: QJsonValue

返回 QJsonValue representing the value for index i .

相当于调用 toArray() .at(i).

返回的 QJsonValue is Undefined , if i is out of bounds, or if isArray() is false.

另请参阅

QJsonValue isUndefined() QJsonArray

PySide2.QtCore.QJsonValue. swap ( other ) ¶

参数: other – QJsonValue

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

PySide2.QtCore.QJsonValue. toArray ( ) ¶

返回类型: QJsonArray

这是重载函数。

Converts the value to an array and returns it.

若 type() is not Array, a QJsonArray() 将被返回。

PySide2.QtCore.QJsonValue. toArray ( defaultValue ) ¶

参数: defaultValue – QJsonArray
返回类型: QJsonArray

Converts the value to an array and returns it.

若 type() is not Array, the defaultValue 将被返回。

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

参数: defaultValue – bool
返回类型: bool

Converts the value to a bool and returns it.

若 type() is not bool, the defaultValue 将被返回。

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

参数: defaultValue – double
返回类型: double

Converts the value to a double and returns it.

若 type() is not Double, the defaultValue 将被返回。

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

参数: defaultValue – int
返回类型: int

Converts the value to an int and returns it.

若 type() is not Double or the value is not a whole number, the defaultValue 将被返回。

PySide2.QtCore.QJsonValue. toObject ( ) ¶

返回类型: QJsonObject

这是重载函数。

Converts the value to an object and returns it.

若 type() is not Object, the QJsonObject() 将被返回。

PySide2.QtCore.QJsonValue. toObject ( defaultValue ) ¶

参数: defaultValue – QJsonObject
返回类型: QJsonObject

Converts the value to an object and returns it.

若 type() is not Object, the defaultValue 将被返回。

PySide2.QtCore.QJsonValue. toString ( ) ¶

返回类型: unicode

Converts the value to a QString and returns it.

若 type() is not String, a null QString 将被返回。

另请参阅

isNull()

PySide2.QtCore.QJsonValue. toString ( defaultValue ) ¶

参数: defaultValue – unicode
返回类型: unicode

Converts the value to a QString and returns it.

若 type() is not String, the defaultValue 将被返回。

PySide2.QtCore.QJsonValue. toVariant ( ) ¶

返回类型: object

Converts the value to a QVariant() .

QJsonValue types will be converted as follows:

Null
Nullptr

另请参阅

fromVariant()

PySide2.QtCore.QJsonValue. type ( ) ¶

返回类型: Type

Returns the type of the value.

另请参阅

Type

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QJsonValue ¶

概要 ¶

函数 ¶

静态函数 ¶

详细描述 ¶

QJsonValueRef ¶