My python function won't return or update the value -

def getmove(win,playerx,playery):      #define variables.     movepos = 75     moveneg = -75     running = 1      #run while loop update mouse's coordinates.     while(running):          mousecoord = win.getmouse()         mousex = mousecoord.getx()         mousey = mousecoord.gety()         print "mouse x = ", mousex         print "mouse y = ", mousey          if mousex >= playerx:             playerx = movepos + playerx             running = 0         elif mousex <= playerx:             playerx = moveneg + playerx                        running = 0         elif mousey >= playery:             playery = movepos + playery                         running = 0         elif mousey <= playery:             playery = moveneg + playery                         running = 0     return playerx,playery  def main():      #create game window.     win = graphwin("python game", 500, 500)     drawboard(win)      #define variables.     playerx = 75     playery = 125     keyx = 325     keyy = 375     running = 1       #create key , player objects, draw key, don't draw player yet.     key = text(point(keyx,keyy),"key")     key.draw(win)      while(running):         print "player x = ", playerx         print "player y = ", playery         drawboard(win)         getmove(win,playerx,playery)         player = circle(point(playerx,playery),22)         player.setfill('yellow')         player.draw(win) main() 

i using graphics library create game. player , key drawn in correct places. however, when calling getmove function, playerx , playery not update. have added debug print statements find values while running game , 75 , 125. help!

in python, integers immutable - when assign new integer value variable, making variable point new integer, not changing old integer pointed to's value was.

(an example of mutable object in python list, can modify , variables pointing list notice change - since list has changed.)

similarly, when pass variable method in python , alter variable points in method, not alter variable points outside of method because new variable.

to fix this, assigned returned playerx,playery variables outside method:

playerx, playery = getmove(win,playerx,playery)