今天遇到了這個需求，於是抽出了這個方法，代碼如下：
//把字符串替換成星號
-(NSString *)replaceStringWithAsterisk:(NSString *)originalStr startLocation:(NSInteger)startLocation lenght:(NSInteger)lenght
{
NSString *newStr = originalStr;
for (int i = 0; i < lenght; i++) {
NSRange range = NSMakeRange(startLocation, 1);
newStr = [newStr stringByReplacingCharactersInRange:range withString:@"*"];
startLocation ++;
}
return newStr;
}
使用實例：
NSString *phoneStr= [self replaceStringWithAsterisk:loginData.phone startLocation:3 lenght:loginData.phone.length -7];