Swift Xcode-beta环境运行代码报Extra Argument in call错误，无其他报错

你出现Extra Argument in call报错的核心原因是Swift 字符串插值的格式化语法使用错误，你当前写的\((format: "%.2f"), 变量名)的语法不符合Swift规范，相当于你给插值传入了两个参数（一个format字符串、一个变量），系统识别为多余参数。

有两种常用修复方式：

方式1：使用String(format:)整体格式化（推荐，代码更简洁） #

你可以把所有变量放到String(format:)的参数列表里，对应前面的格式占位符即可，示例写法：

self.blendShapeLabel.text = String(format: "The blendshapes are %.2f,%.2f,%.2f,%.2f,%.2f,%.2f,%.2f,%.2f,%.2f,%.2f,%.2f,%.2f,%.2f,%.2f,%.2f,%.2f,%.2f,%.2f,%.2f,%.2f,%.2f,%.2f,%.2f,%.2f,%.2f,%.2f,%.2f,%.2f,%.2f,%.2f,%.2f,%.2f,%.2f,%.2f,%.2f,%.2f,%.2f,%.2f,%.2f,%.2f,%.2f,%.2f,%.2f,%.2f,%.2f,%.2f,%.2f,%.2f", 
eyeBlinkR, eyeBlinkL, eyeLookInL, eyeLookInR, eyeLookOutL, eyeLookOutR, eyeLookDownL, eyeLookDownR, eyeLookUpL, eyeLookUpR, eyeSquintL, eyeWideL, eyeSquintR, eyeWideR, mouthL, mouthR, mouthFrownL, mouthFrownR, mouthSmileL, mouthSmileR, mouthDimpleL, mouthDimpleR, mouthStretchL, mouthStretchR, mouthCloseCoeff, mouthPucker, mouthFunnel, mouthRollLower, mouthRollUpper, mouthPressL, mouthPressR, mouthLowerDownL, mouthLowerDownR, mouthUpperUpL, mouthUpperUpR, jawForward, jawLeft, jawRight, jawOpen, cheekPuff, cheekSquintL, cheekSquintR, noseSneerL, noseSneerR, tongueOut, browInnerUp, browDownL, browDownR, browOutterL, browOutterR)

方式2：修改单插值的格式化写法 #

如果你要在每个插值里单独格式化，正确语法是String(format: "%.2f", 变量名)，把原来的\((format: "%.2f"), eyeBlinkR)改成\(String(format: "%.2f", eyeBlinkR))即可，所有插值位置都按这个规则修改就行。

内容的提问来源于stack exchange，提问作者Jay Tikoo