Either expand to an IfExpr to special-case the non-numbers or use number() to force explicit conversions and obtain NaN as under 1.0.

或者扩展 IfExpr 引入非数字的特殊情况，或者像 1.0 那样使用 number() 强制显式转换得到 NaN。

youdao

We obtain an explicit formulae for the conditional distribution laws of the state of the dynamical system with respect to the observed data.

本文讨论非线性随机离散系统状态估值问题的测度变换，推得系统的状态对于观测的条件分布律。

youdao

Other provisions require companies to obtain explicit permission from individuals before using their data.

FORBES: The Upcoming Data Protection Crunch: EU Proposals Raise the Ante for Non-Compliant Companies

In a letter to Path Intelligence CEO Sharon Biggar, Schumer urged the company to obtain the explicit consent of shoppers' through an opt-in policy.

WSJ: Schumer: Don't track shoppers without consent