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Questions tagged [casting]

Casting is a process where an object type is explicitly converted into another type if the conversion is allowed. This process might lead to a change in value.

Some algorithms have significant performance differences for different data-types, for example, calculating the N-dimensional median is much is much faster for integers than float type data. Therefore, the use of casting can be important for code performance.

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Why don't Java's +=, -=, *=, /= compound assignment operators require casting?

Until today, I thought that for example: i += j; Was just a shortcut for: i = i + j; But if we try this: int i = 5; long j = 8; Then i = i + j; will not compile but i += j; will compile fine. Does it mean that in fact i += j; is a shortcut for…
Honza Brabec
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How can I cast int to enum?

How can an int be cast to an enum in C#?
lomaxx
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When should static_cast, dynamic_cast, const_cast and reinterpret_cast be used?

What are the proper uses of: static_cast dynamic_cast const_cast reinterpret_cast C-style cast (type)value Function-style cast type(value) How does one decide which to use in which specific cases?
e.James
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Do I cast the result of malloc?

In this question, someone suggested in a comment that I should not cast the result of malloc. i.e., I should do this: int *sieve = malloc(sizeof(int) * length); rather than: int *sieve = (int *) malloc(sizeof(int) * length); Why would this be the…
Patrick McDonald
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Get int value from enum in C#

I have a class called Questions (plural). In this class there is an enum called Question (singular) which looks like this. public enum Question { Role = 2, ProjectFunding = 3, TotalEmployee = 4, NumberOfServers = 5, …
jim
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Regular cast vs. static_cast vs. dynamic_cast

I've been writing C and C++ code for almost twenty years, but there's one aspect of these languages that I've never really understood. I've obviously used regular casts i.e. MyClass *m = (MyClass *)ptr; all over the place, but there seem to be two…
Graeme Perrow
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How do I check if a string is a number (float)?

What is the best possible way to check if a string can be represented as a number in Python? The function I currently have right now is: def is_number(s): try: float(s) return True except ValueError: return…
Daniel Goldberg
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Change column type in pandas

I want to convert a table, represented as a list of lists, into a Pandas DataFrame. As an extremely simplified example: a = [['a', '1.2', '4.2'], ['b', '70', '0.03'], ['x', '5', '0']] df = pd.DataFrame(a) What is the best way to convert the columns…
user1642513
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Direct casting vs 'as' operator?

Consider the following code: void Handler(object o, EventArgs e) { // I swear o is a string string s = (string)o; // 1 //-OR- string s = o as string; // 2 // -OR- string s = o.ToString(); // 3 } What is the difference between the…
nullDev
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How do I convert a string to a number in PHP?

I want to convert these types of values, '3', '2.34', '0.234343', etc. to a number. In JavaScript we can use Number(), but is there any similar method available in PHP? Input Output '2' 2 '2.34' 2.34 '0.3454545' …
Sara
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Why use static_cast(x) instead of (int)x?

I've heard that the static_cast function should be preferred to C-style or simple function-style casting. Is this true? Why?
Tommy Herbert
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How to convert a factor to integer\numeric without loss of information?

When I convert a factor to a numeric or integer, I get the underlying level codes, not the values as numbers. f <- factor(sample(runif(5), 20, replace = TRUE)) ## [1] 0.0248644019011408 0.0248644019011408 0.179684827337041 ## [4]…
Adam SO
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Convert Int to String in Swift

I'm trying to work out how to cast an Int into a String in Swift. I figure out a workaround, using NSNumber but I'd love to figure out how to do it all in Swift. let x : Int = 45 let xNSNumber = x as NSNumber let xString : String =…
Steve Marshall
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Converting an integer to a string in PHP

Is there a way to convert an integer to a string in PHP?
kman99
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Safely casting long to int in Java

What's the most idiomatic way in Java to verify that a cast from long to int does not lose any information? This is my current implementation: public static int safeLongToInt(long l) { int i = (int)l; if ((long)i != l) { throw new…
Brigham
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