iOS中向浮点类型数的左方间隔指定位数插入符号

/*

*函数名:insertSymbolToNum

*参数1:Num 需要添加的符号的浮点类型数

*参数2:symbol 添加的符号

*参数3:digit 插入的间隔位数

*/

-(NSString *)insertSymbolToNum:(double)Num withSymbol:(NSString *)symbol withDigit:(int)digit

{

NSMutableString *str = [NSMutableString stringWithFormat:@"%.2f",Num];

NSInteger s = [str rangeOfString:@"."].location;

double x = (double)s/digit;

for (int i = 1; i<=x; i++) {

if (i!=x) {

[str insertString:symbol atIndex:s-i*digit];

}

}

return str;

}

///使用方法

NSString *str = [self insertSymbolToNum:12345.321 withSymbol:@"," withDigit:4];

NSLog(@"str is %@",str);