$NoValue

$NoValue

是一个特殊值，可以赋给 InitializationValue[…] 对象，表明由初始化值引用的符号应该初始化为空值.

更多信息

范例

基本范例  (1)

在会话开始时取消云连接：

Wolfram Research (2017)，$NoValue，Wolfram 语言函数，https://reference.wolfram.com/language/ref/$NoValue.html.

文本

Wolfram Research (2017)，$NoValue，Wolfram 语言函数，https://reference.wolfram.com/language/ref/$NoValue.html.

CMS

Wolfram 语言. 2017. "$NoValue." Wolfram 语言与系统参考资料中心. Wolfram Research. https://reference.wolfram.com/language/ref/$NoValue.html.

APA

Wolfram 语言. (2017). $NoValue. Wolfram 语言与系统参考资料中心. 追溯自 https://reference.wolfram.com/language/ref/$NoValue.html 年

BibTeX

@misc{reference.wolfram_2024_$novalue, author="Wolfram Research", title="{$NoValue}", year="2017", howpublished="\url{https://reference.wolfram.com/language/ref/$NoValue.html}", note=[Accessed: 22-November-2024 ]}

BibLaTeX

@online{reference.wolfram_2024_$novalue, organization={Wolfram Research}, title={$NoValue}, year={2017}, url={https://reference.wolfram.com/language/ref/$NoValue.html}, note=[Accessed: 22-November-2024 ]}