iOS字符串替换，字符插入，字符删除

1.字符串替换，（删除也可以用空白替换）

方法：- stringByReplacingOccurrencesOfString:withString:options:range:

样例：

 NSString * string=@"2016-05-05";  
  string=[string stringByReplacingOccurrencesOfString:@"-"withString:@"/"];    
NSLog(@"replaceStr=%@",string);

输入结果如下 
replaceStr=2016/05/05

2.字符串插入
方法 

- (void)insertString:(NSString
*)aString
             atIndex:(NSUInteger)anIndex
样例：

 
+(NSString*)addSeparatorForPriceString:(NSString*)priceStr
{
    NSString* price =
@"3000000";
    NSMutableString* tempStr = price.mutableCopy;
    NSRange range = [price
rangeOfString:@"."];
    NSInteger index =
0;
    if (range.length>0)
    {
       index = range.location;
    }
    else
    {
        index = price.length;
    }
    while ((index-3)>0)
    {
        index-=3;
        [tempStr insertString:@","
atIndex:index];
    }
    tempStr = [tempStr stringByReplacingOccurrencesOfString:@"."
withString:@","].mutableCopy;
    return tempStr;
}