Access with default value: value¶

Overview¶

In many situations such as configuration files, missing values are not exceptional, but may be treated as if a default value was present.

Example

Consider the following JSON value:

{
    "logOutput": "result.log",
    "append": true
}

Assume the value is parsed to a json variable j.

expression	value
`j`	`{"logOutput": "result.log", "append": true}`
`j.value("logOutput", "logfile.log")`	`"result.log"`
`j.value("append", true)`	`true`
`j.value("append", false)`	`true`
`j.value("logLevel", "verbose")`	`"verbose"`

Exceptions

value can only be used with objects. For other types, a basic_json::type_error is thrown.

Last update: May 1, 2022