今天遇到了这个需求，于是抽出了这个方法，代码如下：
//把字符串替换成星号
-(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;
}
使用实例：
NSString *phoneStr= [self replaceStringWithAsterisk:loginData.phone startLocation:3 lenght:loginData.phone.length -7];