function

问题 I took this example from a different question. I am building an R package with Rcpp. I have a function like fun1 (below) that I want to put into its own .cpp file. Then I want to call fun1 with other functions (like fun() does below). I want fun1 in a separate file because I am going to call it from several Rcpp functions that are in different .cpp files. Are there certain include statements and things I need to do to make the fun1 function accessible in the .cpp where fun() is located? Thank

问题 I took this example from a different question. I am building an R package with Rcpp. I have a function like fun1 (below) that I want to put into its own .cpp file. Then I want to call fun1 with other functions (like fun() does below). I want fun1 in a separate file because I am going to call it from several Rcpp functions that are in different .cpp files. Are there certain include statements and things I need to do to make the fun1 function accessible in the .cpp where fun() is located? Thank

问题 I took this example from a different question. I am building an R package with Rcpp. I have a function like fun1 (below) that I want to put into its own .cpp file. Then I want to call fun1 with other functions (like fun() does below). I want fun1 in a separate file because I am going to call it from several Rcpp functions that are in different .cpp files. Are there certain include statements and things I need to do to make the fun1 function accessible in the .cpp where fun() is located? Thank

问题 I am trying to better understand recursion and how return statements work. As such, I'm looking at a piece of code meant to identify the fibonacci number associated with a given term -- in this case, 4. I'm have difficulty understanding the else statement. def f(n): if n == 0: return 0 if n == 1: return 1 else: return f(n-1) + f(n-2) f(4) I have tried using Visualize Python to examine what happens at each step, but I get lost when it hits the else statement. It looks like it is taking the

问题 This code does NOT work: def inc(x): return x + 1 def repeat(f, n): if n == 0: return lambda x: x else: return f( repeat(f, n - 1 ) ) inc_10 = repeat(inc, 10) #TypeError: unsupported operand type(s) for +: 'function' and 'int' ''' # Ideally print(inc_10(0)) # 10 ''' How can I write it in a more Pythonic way or in lambda calculus way ? 回答1: You still need to return a function, not the result of calling f , in the recursive case. # repeat :: (a -> a) -> Integer -> a -> a # repeat _ 0 = id #

问题 This code does NOT work: def inc(x): return x + 1 def repeat(f, n): if n == 0: return lambda x: x else: return f( repeat(f, n - 1 ) ) inc_10 = repeat(inc, 10) #TypeError: unsupported operand type(s) for +: 'function' and 'int' ''' # Ideally print(inc_10(0)) # 10 ''' How can I write it in a more Pythonic way or in lambda calculus way ? 回答1: You still need to return a function, not the result of calling f , in the recursive case. # repeat :: (a -> a) -> Integer -> a -> a # repeat _ 0 = id #

问题 When I'm trying to return my res.data from my function and then console.log it I get undefined but if I console.log it from inside the function I get the normal result const getDefaultState = () => { axios .get("http://localhost:5000/urls/todos") .then((res) => { if (res.data) { console.log(res.data); return res.data; } }) .catch((err) => console.log(err)); }; console.log(getDefaultState()); so I get first (3) [{…}, {…}, {…}] (the normal value) but then from outside I get undefined 回答1: You

问题 When I'm trying to return my res.data from my function and then console.log it I get undefined but if I console.log it from inside the function I get the normal result const getDefaultState = () => { axios .get("http://localhost:5000/urls/todos") .then((res) => { if (res.data) { console.log(res.data); return res.data; } }) .catch((err) => console.log(err)); }; console.log(getDefaultState()); so I get first (3) [{…}, {…}, {…}] (the normal value) but then from outside I get undefined 回答1: You

问题 When I'm trying to return my res.data from my function and then console.log it I get undefined but if I console.log it from inside the function I get the normal result const getDefaultState = () => { axios .get("http://localhost:5000/urls/todos") .then((res) => { if (res.data) { console.log(res.data); return res.data; } }) .catch((err) => console.log(err)); }; console.log(getDefaultState()); so I get first (3) [{…}, {…}, {…}] (the normal value) but then from outside I get undefined 回答1: You

问题 When I'm trying to return my res.data from my function and then console.log it I get undefined but if I console.log it from inside the function I get the normal result const getDefaultState = () => { axios .get("http://localhost:5000/urls/todos") .then((res) => { if (res.data) { console.log(res.data); return res.data; } }) .catch((err) => console.log(err)); }; console.log(getDefaultState()); so I get first (3) [{…}, {…}, {…}] (the normal value) but then from outside I get undefined 回答1: You