>>> def countfist(a):
...     res = {}
...     for i in a:
...         res[i] = "".join(a).count(i[0])
...     return res
...
>>> countfist(new_mystr)
{‘and‘: 3, ‘world‘: 1, ‘itcastcpp‘: 2, ‘itcast‘: 2, ‘hello‘: 1}
>>>
 

>>> name_list=[‘foster‘,"janet",‘jessus‘,‘david‘]
>>> countfist(name_list)
{‘david‘: 2, ‘foster‘: 1, ‘janet‘: 2, ‘jessus‘: 2}
>>>

統計名字列表中，各名字的首字母在名字列表中出現的次數