为什么python只打印字典中的最后一个键？

Question

I was trying the make a function in python and using a for loop to iterate all keys or values from a dictionary and I was trying to assign a global variable inside the function so I can print the keys outside the function but it was only printing the last key:

ships = {
'playerShip1' : cv.imread(r'C:\\Users\\a\\Desktop\\desktopFolders\\pyexample\\seafightShip.jpg', cv.IMREAD_UNCHANGED),
'playership2' : cv.imread(r'C:\\Users\\a\\Desktop\\desktopFolders\\pyexample\\seafightCroped.jpg', cv.IMREAD_UNCHANGED)
}

def att():
global key
for key in ships:
    global shipLoc
    shipLoc = key
    #it works okay here     
    #print(key) 

att()
#quit()

#but it only prints the last key here
print(key)
quit()

Answer 1

It only prints the last key because your print() call is outside of the for loop that iterates over the keys. By the time the program gets to your uncommented print() , the value of key is the final value it was assigned inside the loop. To print all values of key , uncomment the print(key) call inside the loop.

Answer 2

Every iteration of the for loop key receives a new value. Once the for loop ended, only the last value of key is assigned to the variable key .