compare

问题 The comparision operators < <= > >= can be applied for strings as well. So why do we need special function for string comparision: strcmp ? 回答1: Because there are several variations: Depending on the function, the answer to these questions vary: Is it case sensitive? (strcmp vs strcasecmp, strnatcmp vs strnatcasecmp) Depends it depend on the locale? (strcoll does) Can I specify a collation? (strcoll is affected by setlocale ) Additionaly, the comparison operators also give true or false .

问题 I have written 2 functions doing the exact same thing, but I don't know which one is faster and better. How do I compare these 2 functions to see which one is better in terms of performance and everything? 回答1: The timeit module will do ya. 回答2: Once you've found out which function is faster using the timeit module, you can also get more precise details of where the differences are by using the profile module. 来源： https://stackoverflow.com/questions/7956834/how-do-i-compare-python-functions

问题 I need to check whether an std:string begins with "xyz". How do I do it without searching through the whole string or creating temporary strings with substr(). 回答1: I would use compare method: std::string s("xyzblahblah"); std::string t("xyz") if (s.compare(0, t.length(), t) == 0) { // ok } 回答2: An approach that might be more in keeping with the spirit of the Standard Library would be to define your own begins_with algorithm. #include <algorithm> using namespace std; template<class TContainer

问题 I am comparing 2 large CSV file using Perl that's called in a batch file. I put the result in a 3rd file. Currently the file contains other information like headers, and other lines like this: --- file1.txt Wed Mar 7 14:57:10 2018 +++ file2.txt Wed Mar 7 13:56:51 2018 @@ -85217,4 +85217,8 @@ How can the result file only contains the difference ? Thank you. This is my perl: #!/usr/bin/env perl use strict; use warnings; use Text::Diff; my $diffs = diff 'file1.txt' => 'file2.txt'; print $diffs;

问题 I'm new with C programming and I need to get images from two .dat files and compare if both of them are equal. The files first have the number of images, and then some images. I need to return 1 if all of the images are the same. Pic of one of the .dat files: F1.dat The first 20 means 20 "groups" of images. Then 3 4 would mean 3x4 matrix and the rest would be the matrix. The same with the other 19 matrices. I need to go comparing the first matrix of the first file with the first one from the

问题 Assume for simplicity that the data files look like this, sorted on ID: ID | Data1 | Data2 | Data3 | Data4 199 | Tim | 55 | work | $55 345 | Joe | 45 | work | $34 356 | Sam | 23 | uni | $12 Each file has more than 100,000 rows and about 50 columns. I want to compare a 2nd file with the first for new records (new ID ), edits (IDs match but columns 2 or 4 have changed (Data1 and Data3), and Deletes (ID in first file does not exist in the 2nd file). Output is to appear in an Excel file with the

问题 In my custom sorting algorithm, I need to compare numeric types stored as Objects in an array. We can have SByte, Double, Int32, etc values mixed in one array. How can I compare two values of that array in my IComparer implementation? An example. Let's say we have two numeric values: object var1 = (sbyte)-8; object var2 = (double)123.456; It would be nice if code like the following one worked, but it fails: IComparable cmp1 = var1 as IComparable; IComparable cmp2 = var2 as IComparable;

问题 I want compare 2 NSMutableArray values and check which indexPath is different and store this numbers of index in one array. for example I have these NSMutableArray : NSMutableArray *a = [[NSMutableArray alloc]initWithObjects:@"1",@"2",@"3",@"4",@"5",@"6", nil]; NSMutableArray *b = [[NSMutableArray alloc]initWithObjects:@"11",@"2",@"5",@"3",@"53",@"6", nil]; and I want to compare these two NSMutableArray index to index (compare value to value) and tell me that which index of array in these

问题 This question already has answers here : Comparing floating point numbers in C (4 answers) Closed 4 years ago . I am currently writing a greedy algorithm, but I have stumbled upon a problem when comparing floats. I would use code like this: float f = 0; if (f == 0) { // code } I have tested this on a seperate program and it worked fine, but not on the program I am working on. Here is an extract from my own program. float chf2 = fmod(chf, 0.1); float ch3 = chf - chf2; if (chf2 == 0) { /*

问题 I have two dictionary files that I want to compare. I need to know if a value from one dictionary occurs in the other dictionary. The keys are not the same so I can't go based on keys. Goals: Does same value exist in both dictionaries? Print the values that do not occur in the other dictionary. Create a new dictionary with the Keys, values from both the dictionary that match and print dictionary to screen. I'm able to search both dictionaries and find 69 different entries. My issues are: I