comparison-operators

I want to find substring of the string or check if there is no such substring using Twig. On the words, I need analogue of 'strstr' or 'strpos' in php. I googled and searched this issue in stackoverflow but nothing found. Does someone know how to solve this problem? Just searched for the docs , and found this : Containment Operator: The in operator performs containment test. It returns true if the left operand is contained in the right: {# returns true #} {{ 1 in [1, 2, 3] }} {{ 'cd' in 'abcde' }} 来源： https://stackoverflow.com/questions/13007288/find-substring-in-the-string-in-twig

Comparing two instances of the following struct, I receive an error: struct MyStruct1 { Position(const MyStruct2 &_my_struct_2, const int _an_int = -1) : my_struct_2(_my_struct_2), an_int(_an_int) {} std::string toString() const; MyStruct2 my_struct_2; int an_int; }; The error is: error C2678: binary '==' : no operator found which takes a left-hand operand of type 'myproj::MyStruct1' (or there is no acceptable conversion) Why? In C++, struct s do not have a comparison operator generated by default. You need to write your own: bool operator==(const MyStruct1& lhs, const MyStruct1& rhs) { return

I have a class called AString . It is pretty basic: class AString { public: AString(const char *pSetString = NULL); ~AString(); bool operator==(const AString &pSetString); ... protected: char *pData; int iDataSize; } Now I want to write code like this: AString *myString = new AString("foo"); if (myString == "bar") { /* and so on... */ } However, the existing comparison operator only supports if (*myString == "bar") If I omit that asterisk, the compiler is unhappy. Is there a way to allow the comparison operator to compare *AString with const char* ? No, there is not. To overload operator== ,

Resharper suggests that the following be changed from: Type foo = typeof( Foo ); Type bar = typeof( Bar ); if( foo.Equals( bar ) ) { ... } To: if( foo == bar ) { ... } operator == // Summary: // Indicates whether two System.Type objects are equal. // // Parameters: // left: // The first object to compare. // // right: // The second object to compare. // // Returns: // true if left is equal to right; otherwise, false. public static bool operator ==( Type left, Type right ); Equals( Type o ) // Summary: // Determines if the underlying system type of the current System.Type is the // same as the

This question already has an answer here: Why does >= return false when == returns true for null values? 8 answers Why is it that in .NET null >= null resolves as false, but null == null resolves as true? In other words, why isn't null >= null equivalent to null > null || null == null ? Does anyone have the official answer? This behaviour is defined in the C# specification ( ECMA-334 ) in section 14.2.7 (I have highlighted the relevant part): For the relational operators < > <= >= a lifted form of an operator exists if the operand types are both non-nullable value types and if the result type

A few weeks ago, I have read this thread Is < faster than <=? about comparison operators in C . It was said that there is no difference in the performance between < and <= as they are interpreted as same/similar machine commands. At the same time, in our company's "best practices", it was said that we should always use "===" to compare things instead of "==". So, I started to wonder if this is always appropriate as I am used to using the "==" and "typeof ... == " and do not want to change my way of writing :-] Note that this is in the context of JavaScript. So, I have a little research and

I've been reading Douglas Crockford's JavaScript: The Good Parts , and I came across this weird example that doesn't make sense to me: '' == '0' // false 0 == '' // true 0 == '0' // true false == undefined // false false == null // false null == undefined // true The author also goes on to mention "to never use == and != . Instead, always use === and !== ". However, he doesn't explain why the above behavior is exhibited? So my question is, why are the above results as they are? Isn't transitivity considered in JavaScript? alex '' == '0' // false The left hand side is an empty string, and the