利用切片操作,实现一个trim()函数,去除字符串首尾的空格
def trim(s):
if(len(s)==0):
return s
if(s[0]==' '):
return trim(s[1:])
if(s[-1]==' '):
return trim(s[:-1])
return s
if trim(' hello') != 'hello':
print('shibai!')
else:
print('pass!')
if trim('hello ') != 'hello':
print('fail!')
else:
print('pass!')
if trim(' hello ') != 'hello':
print('fail!')
else:
print('pass!')
if trim(' hello world ') != 'hello world':
print('fail!')
else:
print('pass!')
if trim('') != '':
print('fail!')
else:
print('pass!')
if trim(' ') != '':
print('fail!')
else:
print('pass!')
def trim(s):
i=0
j=len(s)-1
if(s==''):
return s
while(s[i]==' '):
i=i+1
if(i==j):
s=''
return s
while(s[j]==' '):
j=j-1
return s[i:j+1]
if trim(' hello') != 'hello':
print('shibai!')
else:
print('pass!')
if trim('hello ') != 'hello':
print('fail!')
else:
print('pass!')
if trim(' hello ') != 'hello':
print('fail!')
else:
print('pass!')
if trim(' hello world ') != 'hello world':
print('fail!')
else:
print('pass!')
if trim('') != '':
print('fail!')
else:
print('pass!')
if trim(' ') != '':
print('fail!')
else:
print('pass!')