Question

Create a new program, called stars.py, for (eventually) drawing a 500x500 pixel picture of the night sky. The stars.py file will define several custom functions. You should write each function and then test it to verify it is working correctly. Make sure you match each function name precisely. Once complete submit it to D2L.

getStarPixelX()

• 1 Input Parameter: a star string
• Return: the x pixel coordinate of the star
• Steps:
  1. Split star string into smaller strings
  2. grab the x coordinate and convert it into a float
  3. calculate the pixel coordinate with the formula: 250 + (250 * x)
  4. return the result

Below are some example function calls and return values. You should test them by having your program call the function and print out the return value. (You can erase your test code later.)

• getStarPixelX("0.0,1.0,0.0,1,-1.5,1") → 250.0
• getStarPixelX("0.5,-0.5,0.0,2,2.0,2") → 375.0

getStarPixelY()

• 1 Input Parameter: a star string
• Return: the y pixel coordinate of the star
• Steps:
  1. Split star string into smaller strings
  2. grab the y coordinate and convert it into a float
  3. calculate the pixel coordinate with the formula: 250 - (250 * y)
  4. return the result

Below are some example function calls and return values. You should test them by having your program call the function and print out the return value. (You can erase your test code later.)

• getStarPixelY("0.0,1.0,0.0,1,-1.5,1") → 0.0
• getStarPixelY("0.5,-0.5,0.0,2,2.0,2") → 375.0

getStarSize()

• 1 Input Parameter: a star string
• Return: the pixel size of the star
• Hint: The formula to convert a star's magnitude to its size is: 10.0/(magnitude + 2)

Below are some example function calls and return values. You should test them by having your program call the function and print out the return value. (You can erase your test code later.)

• getStarSize("0.0,1.0,0.0,1,-1.5,1") → 20.0
• getStarSize("0.5,-0.5,0.0,2,2.0,2") → 2.5

getStarName()

• 1 Input Parameter: a star string
• Return: the name of the star if it has one, else the empty string ("")
• Hint: If a star string has 7 values, then the last value is the star's name

Below are some example function calls and return values. You should test them by having your program call the function and print out the return value. (You can erase your test code later.)

• getStarName("0.0,1.0,0.0,1,-1.5,1,BOB") → "BOB"
• getStarName("0.5,-0.5,0.0,2,2.0,2") → ""

Answer 1

#the following code may throw an error in python2

#drop a comment if something is wrong. check for typos in the function names

#---------------------------------------

def getStarPixelX(a):

    #splits the given string into a list

    a=a.split(",")

    # applies the given formula on the x cordinate

    x=250+(250*float(a[0]))

    return x

print(getStarPixelX("0.0,1.0,0.0,1,-1.5,1"), getStarPixelX("0.5,-0.5,0.0,2,2.0,2"))

def getStarPixelY(a):

    #splits the given string into a list

    a=a.split(",")

    #applies the given formula on the Y cordinate

    y=250-(250*float(a[1]))

    return y

print(getStarPixelY("0.0,1.0,0.0,1,-1.5,1"),getStarPixelY("0.5,-0.5,0.0,2,2.0,2"))

def getStarSize(a):

    #splits the given string into a list

    a=a.split(",")

    #applies the given formula on the magnitude

    size=10.0/(float(a[4])+2)

    return size

print(getStarSize("0.0,1.0,0.0,1,-1.5,1"),

getStarSize("0.5,-0.5,0.0,2,2.0,2"))

def getStarName(a):

    #splits the given string into a list

    a=a.split(",")

    # if te length of the list is 7

    if len(a)==7:

        #return the last element of the list

        return a[-1]

    else:       

        return ""

print(getStarName("0.5,-0.5,0.0,2,2.0,2"),getStarName("0.0,1.0,0.0,1,-1.5,1,BOB"))

#-------------------------OUTPUT---------------------------------------------------

250.0 375.0

0.0 375.0

20.0 2.5

BOB