擅长:python、mysql、java
<pre><code>def myfunc(str_string): # Dont use the str, its a keyword
str_string = str_string.lower()
new_str = ''
for index in range(len(str_string)): # loop through the string length rather string itself
if index % 2 == 0:
new_str += str_string[index].upper()
else:
new_str += str_string[index]
index += 1
return new_str
print(myfunc('Hello World'))
# one liner
str_index = 'Hello World'
print("".join([str_index[i].upper() if i%2==0 else str_index[i].lower() for i in range(len(str_index)) ]))
</code></pre>