python list转换字符串报错TypeError: sequence item 0: expected str instance, int found

今天敲小例子，报了错TypeError: sequence item 0: expected str instance, int found

小例子：list1=[1,'two','three',4]

print(' '.join(list1))

以为会打印 1 two three 4

结果报了错

Traceback (most recent call last):

  File "<pyshell#27>", line 1, in <module>

    print(" ".join(list1))

TypeError: sequence item 0: expected str instance, int found

上网查了资料，说list包含数字，不能直接转化成字符串。

解决办法：print(" ".join('%s' %id for id in list1))

即遍历list的元素，把他转化成字符串。这样就能成功输出1 two three 4结果了。