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1. 比较两个字符串的大小 //第一个参数是要进行比较的字符串, 第二个参数是比较的方法, 是一个枚举的类型 - (NSComparisonResult)compare:(NSString *)string options:(NSStringCompareOptions)mask; 枚举的值: NSStringCompareOptions enum{ NSCaseInsensitiveSearch = 1,//不区分大小写比较 NSLiteralSearch = 2,//区分大小写比较 NSBackwardsSearch = 4,//从字符串末尾开始搜索 NSAnchoredSearch = 8,//搜索限制范围的字符串 NSNumbericSearch = 64//按照字符串里的数字为依据，算出顺序。例如 Foo2.txt < Foo7.txt < Foo25.txt //以下定义高于 mac os 10.5 或者高于 iphone 2.0 可用 , NSDiacriticInsensitiveSearch = 128,//忽略 "-" 符号的比较 NSWidthInsensitiveSearch = 256,//忽略字符串的长度，比较出结果 NSForcedOrderingSearch = 512//忽略不区分大小写比较的选项，并强制返回 NSOrderedAscending

ArrayList<String> dirNo = new ArrayList<String>(); dirNo.add("1"); dirNo.add("2"); dirNo.add("3"); dirNo.add("4"); dirNo.add("5"); dirNo.add("6"); dirNo.add("7"); dirNo.add("8"); dirNo.add("9"); dirNo.add("10"); dirNo.add("11"); System.out.println("max : " + Integer.parseInt(Collections.max(dirNo))); After executing above code, print 9 as output. But actually max value should be 11 . Why am I getting 9 as max ? Since your elements are strings, Collections.max() is returning the value that's the largest lexicographically . If you wish to compare the strings numerically, you need to use the two

In my app, I accidentally used "==" when comparing two NSNumber objects like so: NSNumber *number1; NSNumber *number2; Later on, after these objects' int values were set, I accidentally did this: if (number1 == number2) { NSLog(@"THEY'RE EQUAL"); } And, confusingly, it worked! I could have sworn I was taught to do it this way: if (number1.intValue == number2.intValue) { NSLog(@"THEY'RE EQUAL"); } How did using "==" between the two NSNumber objects work, and why? Does that mean it's okay to compare them that way, or was it just a fluke and this is generally not guaranteed to work every time? It

I have a matrix that is dynamically being changed according to the following code; for( It=all_frames.begin(); It != all_frames.end(); ++It) { ItTemp = *It; subtract(ItTemp, Base, NewData); cout << "The size of the new data for "; cout << " is \n" << NewData.rows << "x" << NewData.cols << endl; cout << "The New Data is: \n" << NewData << endl << endl; NewData_Vector.push_back(NewData.clone()); } What I want to do is determine the frames at which the cv::Mat NewData is a zero matrix. I've tried comparing it to a zero matrix that is of the same size, using both the cv::compare() function and

I need some help with data analysis. I do have two datasets (before & after) and I want to see how big the difference is between them. Before 11330 STAT1 2721 STAT2 52438 STAT3 6124 SUZY After 17401 STAT1 3462 STAT2 0 STAT3 72 SUZY Tried to group them with tapply(before$V1, before$V2, FUN=mean) . But as I am trying to plot it, on x axis am not getting the group name but number instead. How can I plot such tapplied data (frequency on Y axis & group name on X axis)? Also wanted to ask what is the proper command in R to compare such datasets as I am willing to find the difference between them?

I have a very simple view as follows def simple_view(request): documents = request.user.document_set.all() return render(request, 'simple.html', {'documents': documents}) To test the above view in my test case i have the following method which errors out. Class SomeTestCase(TestCase): # ... def test_simple_view(self): # ... some other checks docset = self.resonse.context['documents'] self.assertTrue(self.user.document_set.all() == docset) # This line raises an error # ... The error i get is AssertionError: False is not true . I have tried printing both the querysets and both are absolutely

How is the y.size() = 4 in the following? The values in y are {11, 2, 4, 7} How does one arrive at this? What are a and b in the operator() function for each iteration of the set. I don't understand the construction of y and I can't find anything online that explains this situation. Thank You #include <iostream> #include <set> struct C { bool operator()(const int &a, const int &b) const { return a % 10 < b % 10; } }; int main() { std::set<int> x({ 4, 2, 7, 11, 12, 14, 17, 2 }); std::cout << x.size() << std::endl; std::set<int, C> y(x.begin(), x.end()); std::cout << y.size() << std::endl; std:

I have searched a lot and tried on my own too, but couldn't find solution for this particular problem. For every 2 rows ('key' is common), I have to find mismatches in every column and highlight them in an organized way like below. The output should be in the following format: COLUMN_NAME is not matching for records below: PRINT COMPLETE RECORDS ... COLUMN_NAME is not matching for records below: PRINT COMPLETE RECORDS ... COLUMN_NAME is not matching for records below: PRINT COMPLETE RECORDS ... Input Data (it's a data frame): key V1 V2 V3 V4 V5 a1 1 2 3 4 5 a1 1 3 9 4 5 a5 2 1 4 7 5 a5 2 1 4 7

I'm using the SIFT algorithm to determine the level of similarity between two images. I managed to get the list of descriptors for image but I cant seem to figure what to do next. My problem is that I have a different number of descriptors and their order is maybe not the same. What is the best way to compare these descriptors? Thanks. Basic euclidean distance together with a heuristic that stipulated that a match is only accepted if it is significantly better than the second best match. As advocated by the (co) inventer, Lowe For each descriptor in image A, find its nearest neighbor in image