题目描述
请实现一个函数，将一个字符串中的每个空格替换成“%20”。例如，当字符串为We Are Happy.则经过替换之后的字符串为We%20Are%20Happy。
思路
先遍历找到多少个空格，然后开辟数组填充
def replaceSpace(s):
len_s = len(s)
space_count = 0
for i in s:
if i == ' ':
space_count += 1
s_len = 2 * space_count + len_s
new_s = [' '] * s_len
j = 0
for i in range(len(s)):
if s[i] == ' ':
new_s[j] = "%"
new_s[j+1] = "2"
new_s[j+2] = "0"
j += 3
else:
new_s[j] = s[i]
j += 1
return (''.join(new_s))
print(replaceSpace('We Are Happy'))