105 lines
2.4 KiB
Julia
105 lines
2.4 KiB
Julia
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+(2, 2)
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versioninfo()
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# FUNCTIONS IN JULIA 1.0 (0.7+)
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# ----------------------
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# * A function maps a tuple of arguments to a return value
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# I Creating basic Functions
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# 1 using the function keyword
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#Create a function named my_addition
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#Takes two arguments
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#Return the addition of the two values
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function my_addition(x, y)
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return x + y
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end
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# 2 Calling a function
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#Call the function with two argument values
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my_addition(3, 4)
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# 3 Built-in functions
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#The plus, +, symbol (as other arithmetical symbols) are built-in functions
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+(3, 4)
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# 4 Using a Unicode symbol as a function name
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function Σ(x, y)
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return x + y
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end
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Σ(3, 4)
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# II Anonymous functions
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# * Functions can be assigned to variables
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# * Functions can be used as arguments
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# * Functions can be returned as values
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# 1 An anonymous function
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x -> x^2 + 3
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# 2 A function as an argument
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#Passing the round() function as argument to the map() function
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map(round, [2.1, 3.4, 7.9])
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#Passing an anonymous function as an arguemt to the map() function
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map(x -> x^2, [2, 3, 4])
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# III Tuples and functions
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# * Tuples are immutable collections
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# 1 Examples of tuples
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my_tuple = (1, "Julia", 7)
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typeof(my_tuple)
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# * Single value tuple must have a comma
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my_second_tuple = (4,)
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typeof(my_second_tuple)
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# 2 Indexing a tuple
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length(my_tuple)
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my_tuple[2]
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# 3 Tuple indexing
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# * Named tuple creates a name for each element
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my_other_tuple = (a = 4, b = "Julia", c = 3)
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#Indexing tuple by name
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my_other_tuple.b
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# 4 Function returns
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# * Multiple return values of a function are tuples
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function my_function(a, b)
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return a + b, a - b
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end
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#Calling the function
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my_function(10, 5)
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#Looking up the type of the function return
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typeof(my_function(10, 5))
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#This allows for each element to be given a variable
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r, s = my_function(10, 5)
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r
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s
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# IV Functions with keyword arguments
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# * Keyword arguments are added after semi-colon
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# * Their order is not explicit
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# * Default values are addded
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# 1 Creating a function with a keyword argument
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function my_keyword_function(x, y; z = 3)
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return x + y + z
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end
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# * Omission of keyword argument uses default
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my_keyword_function(1, 2)
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# * Keyword argument names must be used
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my_keyword_function(1, 2, z = 10)
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# 4 Use of dot notation for functions
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# * Passes a collection elementwise to a function
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# * Use instead of map()
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sin.([0., π/2., π, 3/2. * π, π])
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