"""
1.寫一個生成式能夠產生的數(shù)據(jù)為:1,2,27,256,3125,...9**9
"""

    gen1=(x**x for x in range(1,10))
    
    for i in gen1:
        print(i)



"""
2.寫一個生成式能夠產生1-10中所有半徑是偶數(shù)的圓的面積
"""
    import math
    gen2=(math.pi*(r**2) for r in range(1,11) if r%2 == 0 )
    
    for x in gen2:
        print(x)


"""
3.寫一個生成式交換字段的鍵和值,產生一個新的字典
"""
    dict1={'a':'1','b':'2','c':'3'}
    dict2={}
    gen3=(dict2.setdefault(dict1[x],x) for x in dict1)
    
    print(next(gen3))
    print(next(gen3))
    print(next(gen3))
    print(dict2)