I need to test this type of code bellow:
list = [1,2,3,4]
def getData(list):
return list[0] + list[1]
def processData():
data = getData(list)
multiply = data*data
return multiply
def test_functions():
assert getData([0,1]) == 1
assert processData() == 1
How to tell the test I need data = getData([0,1]), so basically replace data with my test values.
Related
I would like to have a bunch of generators in my config dict. So I tried this:
#yaml.register_class
class UniformDistribution:
yaml_tag = '!uniform'
#classmethod
def from_yaml(cls, a, node):
for x in node.value:
if x[0].value == 'min':
min_ = float(x[1].value)
if x[0].value == 'max':
max_ = float(x[1].value)
def f():
while True:
yield np.random.uniform(min_, max_)
g = f()
return g
However, the parser never returns because generators are used internally to resolve reference like &A and *A. Therefore, something like returning (g,) is a fairly simple workaround, but I would prefer a solution where I don't need the additional and very confusing index 0 term in next(config['position_generator'][0]).
Any Ideas?
This wrapper adapted from a different question did exactly what I was looking for.
class GeneratorWrapper(Generator):
def __init__(self, function, *args):
self.function = function
self.args = args
def send(self, ignored_arg):
return self.function(*self.args)
def throw(self, typ=None, val=None, tb=None):
raise StopIteration
#yaml.register_class
class UniformDistribution:
yaml_tag = '!uniform'
#classmethod
def from_yaml(cls, constructor, node):
for x in node.value:
value = float(x[1].value)
if x[0].value == 'min':
min_ = value
if x[0].value == 'max':
max_ = value
return GeneratorWrapper(np.random.uniform, min_, max_)
Apologies , but am new to scala... learning it, now.
I have been trying to complete a excercise where the ask was as follows :-
// Write a function isPerfectNumber which takes integer input and returns String output.
// It finds if a number is perfect, and returns true if perfect, else returns false
// Write a higher order function myHigherOrderFunction which takes isPerfectNumber and intList as input, and returns a List of Strings which contain the output if the number is perfect or not using map.
Perfect Number :
https://rosettacode.org/wiki/Perfect_numbers
just go to the scala section
My Code :
object ListMapHigherOrder{
def main(args:Array[String])
{
val intRes = args.toList
val intList: List[Int] = intRes.map(_.toInt).toList
def isPerfectNumber(input: Int) :String =
{
var check_sum = ( (2 to math.sqrt(input).toInt).collect { case x if input % x == 0 => x + input / x} ).sum
if ( check_sum == input - 1 )
return "true"
else
return "false"
}
def myHigherOrderFunction(argFn: Int => String, argVal:List[Int]): List[String] = { argVal.map(argFn) }
println(myHigherOrderFunction(isPerfectNumber, intList))
}
}
Code execution : scala ScalaExcercise12.scala 1 6 13
Expected Output : List(false , true , false)
the code gives expected output, am not sure how the backend testing is being done.... it just dosent pass the test.
Is there any issue with the code? - i did like to fix it , but cant i see anything wrong/missing especially because i am getting the same output as desired :(
object ListMapHigherOrder{
def main(args:Array[String])
{
val intRes = args.toList
val intList: List[Int] = intRes.map(x=>x.toInt)
def isPerfectNumber(input: Int) :String =
{
var sum = 0
for(i <- 1 until input){
if(input % i == 0)
sum = sum+i
}
if ( sum == input )
return "true"
else
return "false"
}
def myHigherOrderFunction(argFn: Int => String, argVal:List[Int]): List[String] = { argVal.map(argFn) }
println(myHigherOrderFunction(isPerfectNumber, intList))
}
}
**This worked for me
I receive a List[DataFrame] and I want to store each df in a variable. Some values always exist in the list:
val routes = dataframes(0)
val stops = dataframes(1)
But other ones may also come so the size list is variable.
How could I perform a safely access to a index of list that may be out of bounds? I thought that with Some() and handling the result it would works:
val fare_attributes : Option[DataFrame] = Some(dataframes(10))
fare_attributes match {
case Some(fare) => upload())
println("fare_attributes uploaded")
case None => println("No fare_attributes found")
}
But I receive: java.lang.IndexOutOfBoundsException: 2
You can use .lift on your list:
val fare_attributes : Option[DataFrame] = dataframes.lift(10)
I think you will have to rely on checking the length of the list before accessing the indexed value. You may want to implement some wrapper function to do so. So that it isn't done repeatedly.
You can be a bit "elegant" about it with currying with two parameter lists. So that your code is a bit concise. Here's a sample which you may improve.
def safeList(list: List[Int])(index: Int): Int = {
if (index < list.length) list(index)
else 0
}
val x = List(1, 2 ,3 )
val y = safeList(x)(_)
val a = y(0) // returns 1
val b = y(1) // returns 2
val c = y(4) // returns 0
I had a piece of code:
def this(vectors: List[DenseVector[Double]]) {
this(vectors.length)
var resultVector = vectors.head
for (vector <- vectors) {
resultVector = kron(resultVector.toDenseMatrix, vector.toDenseMatrix).toDenseVector
}
_vector = resultVector
}
It worked just the way I wanted it to work. The problem is that I needed complex values in stead of doubles. After importing breeze.math.Complex, I changed the code to:
def this(vectors: List[DenseVector[Complex]]) {
this(vectors.length)
var resultVector = vectors.head
for (vector <- vectors) {
resultVector = kron(resultVector.toDenseMatrix, vector.toDenseMatrix).toDenseVector
}
_vector = resultVector
}
This however results into the errors:
Error:(42, 26) could not find implicit value for parameter impl: breeze.linalg.kron.Impl2[breeze.linalg.DenseMatrix[breeze.math.Complex],breeze.linalg.DenseMatrix[breeze.math.Complex],VR]
resultVector = kron(resultVector.toDenseMatrix, vector.toDenseMatrix).toDenseVector
^
Error:(42, 26) not enough arguments for method apply: (implicit impl: breeze.linalg.kron.Impl2[breeze.linalg.DenseMatrix[breeze.math.Complex],breeze.linalg.DenseMatrix[breeze.math.Complex],VR])VR in trait UFunc.
Unspecified value parameter impl.
resultVector = kron(resultVector.toDenseMatrix, vector.toDenseMatrix).toDenseVector
^
Is this a bug or am I forgetting to do something?
I found the problem in the following way:
I first rewrote the function to use less matrix conversions
As there was a problem with the implicit impl variable of kron, I also rewrote the function call to explicitly state which variable to use to use
.
def this(vectors: List[DenseVector[Complex]]) {
this(vectors.length)
var resultMatrix = vectors.head.toDenseMatrix
for (i <- 1 until vectors.length) {
resultMatrix = kron(resultMatrix, vectors(i).toDenseMatrix)(kron.kronDM_M[Complex, Complex, DenseMatrix[Complex], Complex])
}
_vector = resultMatrix.toDenseVector
}
This showed me that there was no ScalarMulOp for V2, M, DenseMatrix[RV] where M is a Matrix[V1], V1 and V2 are the input types and RV is the output type of the ScalarMulOp
Digging through the source code of breeze I found in DenseMatrixOps that there only was an implicit ScalarMulOp for the above types if V1, V2 and RV are of type Int, Long, Float and Double. By copying the function and making it specific for Complex numbers, I was able to get the kronecker product to work. Now I could also remove the explicit use of (kron.kronDM_M[Complex, Complex, DenseMatrix[Complex], Complex]). The ScalarMulOp function in question is:
implicit def s_dm_op_Complex_OpMulScalar(implicit op: OpMulScalar.Impl2[Complex, Complex, Complex]):
OpMulScalar.Impl2[Complex, DenseMatrix[Complex], DenseMatrix[Complex]] =
new OpMulScalar.Impl2[Complex, DenseMatrix[Complex], DenseMatrix[Complex]] {
def apply(b: Complex, a: DenseMatrix[Complex]): DenseMatrix[Complex] = {
val res: DenseMatrix[Complex] = DenseMatrix.zeros[Complex](a.rows, a.cols)
val resd: Array[Complex] = res.data
val ad: Array[Complex] = a.data
var c = 0
var off = 0
while (c < a.cols) {
var r = 0
while (r < a.rows) {
resd(off) = op(b, ad(a.linearIndex(r, c)))
r += 1
off += 1
}
c += 1
}
res
}
implicitly[BinaryRegistry[Complex, Matrix[Complex], OpMulScalar.type, Matrix[Complex]]].register(this)
}
I am very new to Scala. I have been assigned the task of coding the Fast Fibonacci algorithm. I am finding it difficult when it comes to actually calling the function. The function takes a tuple of two and returns a tuple of two as a result. I don't know if my logic for fibStep is correct but I will get to that as soon as I can actually test the function. The following is what I have so far:
def fastFib(x: Long ): Long = {
def fibStep(x:(Long, Long)): (Long, Long) = {
//setting temporary variables a and b
def a = x._1
def b = x._2
//applying the fast Fibonacci algorithm
def c = a * (b * 2 - a)
def d = a * a + b * b
if (c+d % 2 == 0) return (c,d)
else return (d, c+d)
}
def tuple = (x-1,x-2)
return fibStep(tuple)
}
I need to pass the tuple (x-1,x-2) to fibStep. How do I do it? Thanks
The problem is in return statement. You trying to return tuple, instead of Long.
Fix:
def fastFib(x: Long ): Long = {
...
return fibStep(tuple)._1 // or ._2
}
Note: I'm not sure if your algorithm is correct
You've got a number of problems here.
def is used to define functions
val should be used to define variables
return should not be used. You 'return' a result simply by it being the last value in an expression.
A tuple is defined simply using parenthesis:
val myTuple = (1,2)
With this information you should be able to make a better attempt at it.