append和replace的几个小问题

# coding=gbk

guests = ['apple', 'boy', 'cat', 'dog'] 

print(guests)

guests_update = guests.replace('apple','egg')

print(guests_update)

报错：AttributeError: 'list' object has no attribute 'replace'

解决：

guests = ['apple', 'boy', 'cat', 'dog']

guests = str(guests)

append报错

# coding=gbk

guests = ['apple', 'boy', 'cat', 'dog']

guests = str(guests)

print(guests) 

guests_update = guests.replace('apple','egg')

print(guests_update)

guests_update.append('frog')

print(guests_update)

报错：AttributeError: ‘str‘ object has no attribute ‘append‘

解释：Of course not, because it's a string and you can't append to string. String are immutable.

解决：在str（）前append

# coding=gbk

guests = ['apple', 'boy', 'cat', 'dog']

guests.append('frog')

print(guests)