comparison

问题 i was trying to compare the difference between 2 dates, but it seems the results are pretty wrong, for example this code: $datetime1 = new DateTime('2009-10-11'); $datetime2 = new DateTime('2009-10-13'); $interval = $datetime1->diff($datetime2); echo $interval->format('%R%a days')."<br />"; $datetime1 = new DateTime('2009-10-11'); $datetime2 = new DateTime('2009-10-15'); $interval2 = $datetime1->diff($datetime2); echo $interval2->format('%R%a days')."<br />"; if($interval == $interval2){ echo

问题 I'm trying to determine if two NSSets are "equal" but not in the sense of isEqualToSet. Items in the two sets are the same class but are not the same object, or even references to the same object. They will have one property that is the same though - let's call it 'name'. Is my best bet in comparing these two sets to do a simple set count test, then a more complex objectsPassingTest: on each item in one set, making sure an item with the same name is in the other set? I'm hoping that something

问题 I'm trying to determine if two NSSets are "equal" but not in the sense of isEqualToSet. Items in the two sets are the same class but are not the same object, or even references to the same object. They will have one property that is the same though - let's call it 'name'. Is my best bet in comparing these two sets to do a simple set count test, then a more complex objectsPassingTest: on each item in one set, making sure an item with the same name is in the other set? I'm hoping that something

问题 This questions involves 2 different implementations of essentially the same code. First, using delegate to create a Comparison method that can be used as a parameter when sorting a collection of objects: class Foo { public static Comparison<Foo> BarComparison = delegate(Foo foo1, Foo foo2) { return foo1.Bar.CompareTo(foo2.Bar); }; } I use the above when I want to have a way of sorting a collection of Foo objects in a different way than my CompareTo function offers. For example: List<Foo>

问题 I work on large database (hundreds of GB) and Mysql now gives me more or less satisfaction. I hesitate to cassandra on launch. What I want to know everything before, so this kind of DBMS NoSQL is supposed to be faster than MySQL? Several points: The change in the number of column on a row In Mysql, they must all be defined in advance. The columns set in the structure of the table. NoSQL in, they can be varied. There is real difference performance on a fixed structure ? and why ? Do not make

问题 I'm creating a basic program that will use a GUI to get a price of an item, then take 10% off of the price if the initial price is less than 10, or take 20% off of the price if the initial price is greater than ten: import easygui price=easygui.enterbox("What is the price of the item?") if float(price) < 10: easygui.msgbox("Your new price is: $"(float(price) * 0.1)) elif float(price) > 10: easygui.msgbox("Your new price is: $"(float(price) * 0.2)) I keep getting this error though: easygui

问题 I'm creating a basic program that will use a GUI to get a price of an item, then take 10% off of the price if the initial price is less than 10, or take 20% off of the price if the initial price is greater than ten: import easygui price=easygui.enterbox("What is the price of the item?") if float(price) < 10: easygui.msgbox("Your new price is: $"(float(price) * 0.1)) elif float(price) > 10: easygui.msgbox("Your new price is: $"(float(price) * 0.2)) I keep getting this error though: easygui

问题 Can someone please explain to me why the output from the following code is saying that arrays are not equal ? int main() { int iar1[] = {1,2,3,4,5}; int iar2[] = {1,2,3,4,5}; if (iar1 == iar2) cout << "Arrays are equal."; else cout << "Arrays are not equal."; return 0; } 回答1: if (iar1 == iar2) Here iar1 and iar2 are decaying to pointers to the first elements of the respective arrays. Since they are two distinct arrays, the pointer values are, of course, different and your comparison tests not

问题 Can someone please explain to me why the output from the following code is saying that arrays are not equal ? int main() { int iar1[] = {1,2,3,4,5}; int iar2[] = {1,2,3,4,5}; if (iar1 == iar2) cout << "Arrays are equal."; else cout << "Arrays are not equal."; return 0; } 回答1: if (iar1 == iar2) Here iar1 and iar2 are decaying to pointers to the first elements of the respective arrays. Since they are two distinct arrays, the pointer values are, of course, different and your comparison tests not

问题 Can someone please explain to me why the output from the following code is saying that arrays are not equal ? int main() { int iar1[] = {1,2,3,4,5}; int iar2[] = {1,2,3,4,5}; if (iar1 == iar2) cout << "Arrays are equal."; else cout << "Arrays are not equal."; return 0; } 回答1: if (iar1 == iar2) Here iar1 and iar2 are decaying to pointers to the first elements of the respective arrays. Since they are two distinct arrays, the pointer values are, of course, different and your comparison tests not