casting

std::lexical_cast – is there such a thing?

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Only partially. C++11 <string> has std::to_string for the built-in types: [n3290: 21.5/7]: string to_string(int val); string to_string(unsigned val); string to_string(long val); string to_string(unsigned long val); string to_string(long long val); string to_string(unsigned long long val); string to_string(float val); string to_string(double val); string to_string(long double val); Returns: Each function returns a string object holding the character representation … Read more

Java casting in interfaces

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When you cast o1 and o3 with (I2), you tell the compiler that the class of the object is actually a subclass of its declared type, and that this subclass implements I2. The Integer class is final, so o3 cannot be an instance of a subclass of Integer: the compiler knows that you’re lying. C1 … Read more

MySQL: Typecasting NULL to 0

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Use IFNULL(column, 0) to convert the column value to zero. Alternatively, the COALESCE function will do the same thing: COALESCE(column, 0), except COALESCE is ANSI-compliant, IFNULL is not COALESCE takes an arbitrary number of columns/values and will return the first non-null value passed to it.

Casting LinkedHashMap to Complex Object

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You can use ObjectMapper.convertValue(), either value by value or even for the whole list. But you need to know the type to convert to: POJO pojo = mapper.convertValue(singleObject, POJO.class); // or: List<POJO> pojos = mapper.convertValue(listOfObjects, new TypeReference<List<POJO>>() { }); this is functionally same as if you did: byte[] json = mapper.writeValueAsBytes(singleObject); POJO pojo = mapper.readValue(json, … Read more

C# : ‘is’ keyword and checking for Not

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if(!(child is IContainer)) is the only operator to go (there’s no IsNot operator). You can build an extension method that does it: public static bool IsA<T>(this object obj) { return obj is T; } and then use it to: if (!child.IsA<IContainer>()) And you could follow on your theme: public static bool IsNotAFreaking<T>(this object obj) { … Read more