判断NSDictionary是否包含某个键

//方法一： if ([[dictionary allKeys] containsObject:key) {    // contains key} //方法二：if ([dictionary objectForKey:key]) {  //objectForKey will return nil if a key doesn't exists.    // contains key}

转自：http://blog.sina.com.cn/s/blog_65c178a801018hsd.html