def xuanze_sort (shu):
    n =len(shu)
    for i in range(n):
        min =i
        for j in range(i,n-1) :
            if shu[min] >shu[j+1] :
                min =j+1
        shu[i],shu[min]=shu[min],shu[i]

list1=["1","4","7","5"]
print(list1)
xuanze_sort(list1)
print(list1)