Question

我想将具有此格式50.3332W的字符串坐标转换为等效的浮点表示-50.3332。

目前我有这样的事情，但它只是替换了W字符，并在最后放置了减号。

NSString *newtest = [_myTextField.text stringByReplacingOccurrencesOfString:@"W" withString:@"-"];

任何有关此方面的帮助都会有所帮助。

Answer 1

// *** Your string value ***
NSString *value = @"50.3332W";

// *** Remove `W` from string , convert it to float and make it negative by multiplying with -1. 
CGFloat floatValue = [[value stringByReplacingOccurrencesOfString:@"W" withString:@""] floatValue] * -1;

// ** Result negative float value without `W` **
NSLog(@"%f",floatValue);

Answer 2

试试这个方法：

- (float)coordinateToFloat:(NSString*)coordinateString {
    NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:@"(\\d+\\.?\\d+?)(W)" options:NSRegularExpressionCaseInsensitive error:nil];
    NSString* preffixString = [regex stringByReplacingMatchesInString:coordinateString options:0 range:NSMakeRange(0, coordinateString.length) withTemplate:@"$2$1"];
    NSString* normalizedString = [preffixString stringByReplacingOccurrencesOfString:@"W" withString:@"-"];
    return normalizedString.floatValue;
}

然后，您可以这样称呼它：

[self coordinateToFloat:@"50.3332W"]; // Returns -50.3332
[self coordinateToFloat:@"50.3332"]; // Returns 50.3332

Regex Demo

将坐标字符串转换为float

2 个答案: