my_list = [(56, 43), (-31, 21, 23), (51, -65, 26), (24, 56)]

print("该列表为：")
print(my_list)

my_result = [sub for sub in my_list if all(elem >= 0 for elem in sub)]

print("正整数元素为：")
print(my_result)

该列表为：
[(56, 43), (-31, 21, 23), (51, -65, 26), (24, 56)]
正整数元素为：
[(56, 43), (24, 56)]