将 NSMutableString 转换为浮点值

Question

在我的应用程序中，我从一堆滑块获取值并将它们转换为 AppDelegate 中的 NSMutableString。然而，我需要稍后回忆这些值，以便我可以用它们进行一些计算，但我无法将这些值重新转换回浮点数，我每次都只是得到 0。我该怎么做才能将 NSMutableString 转换为浮点值？

这是我的视图控制器代码，它尝试从委托获取 NSMutable 字符串，转换它们并进行计算。

-(IBAction)sliderValue:(id)sender {

AppDelegate *appDelegate = (AppDelegate *)[[UIApplication sharedApplication] delegate];



float x1,x2,x3,x4,x5,x6,x7,x8,x9,x10,x11,x12,x13,x14,x15,x16,x17,x18,x19,x20,compat;



x1 = [appDelegate.x1 floatValue];
x2 = [appDelegate.x2 floatValue];
x3 = [appDelegate.x3 floatValue];
x4 = [appDelegate.x4 floatValue];
x5 = [appDelegate.x5 floatValue];
x6 = [appDelegate.x6 floatValue];
x7 = [appDelegate.x7 floatValue];
x8 = [appDelegate.x8 floatValue];
x9 = [appDelegate.x9 floatValue];
x10 = [appDelegate.x10 floatValue];
x11 = [appDelegate.x11 floatValue];
x12 = [appDelegate.x12 floatValue];
x13 = [appDelegate.x13 floatValue];
x14 = [appDelegate.x14 floatValue];
x15 = [appDelegate.x15 floatValue];
x16 = [appDelegate.x16 floatValue];
x17 = [appDelegate.x17 floatValue];
x18 = [appDelegate.x18 floatValue];
x19 = [appDelegate.x19 floatValue];
x20 = [appDelegate.x20 floatValue];

compat = (40-(fabsf(x1-x11)+fabsf(x3-x13)+fabsf(x6-x16)+fabsf(x8-x18))+(x2+x5+x7+x10+x12+x15+x17+x20)*(1-fabsf(x10-x20)/10)/2+(2-fabsf(x4-x14)/5)*(x5+x15)/2);


NSMutableString *strAnswer = [[NSMutableString alloc] initWithString:@"Your Compatibility is "];
NSString *score = [[NSString alloc] initWithFormat:@"%.2f",x2];


[strAnswer appendString:score];
[strAnswer appendString:@" % "];
result.text = appDelegate.x2;

UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"The Results Are IN!!" message:strAnswer delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil, nil];

[alert show];

我到底

如何实现这里的 NSScanner 方法？

Answer 1

使用 floatValue NSString 方法或 NSScanner，更强大、更灵活。我个人更喜欢后者，因为如果接收器不以浮点数的有效文本表示形式开头，则 floatValue 返回 0.0。因此您无法区分 @"0.0" 和 @"completegarbage"。

Answer 2

像这样的东西

NSMutableString *str = [[NSMutableString alloc] init];
[str setString:@"123.4"];

float f = [str floatValue];