Python Zelle Graphics & While loop

I'm trying to create non-overlapping rectangle flashcards and place them at random locations in Zelle Graphics. xMin and yMin is the coordinate of the upper left corner, and xMax and yMax is of the lower right corner of the rectangle. I tried generating random (xCenter,yCenter) coordinate to make a new rectangle, and make a check if the new rectangle overlaps any existing rectangles. If it's overlapped then generate new random points until it's not overlapped anymore.

I got the function for checking overlap, but I'm having trouble with the while loop afterwards. I'm a beginner at Python, so I'd very appreciate your help!

from graphics import *
from random import randrange *

def checkLocation(xMin,xMax,yMin,yMax,xMinList,xMaxList,yMinList,yMaxList):
    for x in range (xMin,xMax):
        for y in range (yMin,yMax):
            for i in range(len(xMinList)):
                if xMinList[i] < x < xMaxList[i] and yMinList[i] < y < yMaxList[i]:
                    return False 
    #if the new rectangle isn't overlapping, append its 4 corner into the list for future comparison:                
    xMinList.append(xMin)
    xMaxList.append(xMax)
    yMinList.append(yMin)
    yMaxList.append(yMax)

    return xMinList,xMaxList,yMinList,yMaxList



def main():
    win = GraphWin("Flash Card", 800,800)
    xCenter, yCenter = randrange (200,600), randrange (200,600) #display the words from the text in randomly generated locations                   
    xMin = xCenter - 50
    xMax = xCenter + 50

    yMin = yCenter - 50
    yMax = yCenter + 50

    xMinList = [300,500,200,100,600] #I hard coded these 4 lists for the purpose of testing
    xMaxList = [350,580,220,140,650]

    yMinList = [100,500,300,600,400]
    yMaxList = [160,540,325,680,450]

    #while checkLocation is False (location overlapping), check again until it's True (not overlapping)
    while not checkLocation(xMin,xMax,yMin,yMax,xMinList,xMaxList,yMinList,yMaxList):
        checkLocation(xMin,xMax,yMin,yMax,xMinList,xMaxList,yMinList,yMaxList)
    xMinList, xMaxList,yMinList,yMaxList =  checkLocation(xMin,xMax,yMin,yMax,xMinList,xMaxList,yMinList,yMaxList)


    rect = Rectangle (Point(xMin,yMin),Point(xMax,yMax))
    rect.draw(win)

main()

Most of your issues stem from your definition and use of the function checkLocation(): sometimes it returns a boolean, sometimes a tuple of lists; you don't seem to be aware that it updates the lists in question so they don't need to be returned and reassigned; one time you seem to call it for no reason at all.

I've reworked your code below to draw ten flash cards that don't overlap -- it's mostly the same code just put into a more logical order:

from graphics import *
from random import randrange

def checkLocation(xMin, xMax, yMin, yMax, xMinList, xMaxList, yMinList, yMaxList):
    for x in range(xMin, xMax):
        for y in range(yMin, yMax):
            for i in range(len(xMinList)):
                if xMinList[i] < x < xMaxList[i] and yMinList[i] < y < yMaxList[i]:
                    return False

    # if the new rectangle isn't overlapping, append its 4 corner into the list for future comparison:
    xMinList.append(xMin)
    xMaxList.append(xMax)
    yMinList.append(yMin)
    yMaxList.append(yMax)

    return True

def main():
    win = GraphWin("Flash Card", 800, 800)

    xMinList = []
    xMaxList = []

    yMinList = []
    yMaxList = []

    for _ in range(10):

        xCenter, yCenter = randrange(200, 600), randrange(200, 600)
        xMin = xCenter - 50
        xMax = xCenter + 50

        yMin = yCenter - 50
        yMax = yCenter + 50

        # while checkLocation is False (location overlapping), check again until it's True (not overlapping)
        while not checkLocation(xMin, xMax, yMin, yMax, xMinList, xMaxList, yMinList, yMaxList):
            # display the words from the text in randomly generated locations
            xCenter, yCenter = randrange(200, 600), randrange(200, 600)
            xMin = xCenter - 50
            xMax = xCenter + 50

            yMin = yCenter - 50
            yMax = yCenter + 50

        rect = Rectangle(Point(xMin, yMin), Point(xMax, yMax))
        rect.draw(win)

    win.getMouse() # Pause to view result
    win.close()    # Close window when done

main()

Initially, your code didn't run at all due to this incorrect import:

from random import randrange *