python的string.strip(s[, chars])方法的各种小细节
下面的英文说明是官方给出：
string.strip(s[, chars])
Return a copy of the string with leading and trailing characters removed. If chars is omitted or None, whitespace characters are removed. If given and not None, chars must be a string; the characters in the string will be stripped from the both ends of the string this method is called on.
Changed in version 2.2.3: The chars parameter was added. The chars parameter cannot be passed in earlier 2.2 versions.
下面例子中字符以tab抬头，以空格结尾。
line=' hello happybks! '
print '*'+line.strip()+'*'
print '*'+line.strip(' ')+'*'
print '*'+line.strip(' ')+'*'
print '*'+line.strip('h')+'*'
输出结果如下：
*hello happybks!* *hello happybks!* *hello happybks!* * hello happybks! *
可以发现不传参数，则会把字符串开头和结尾的空格、tab全部删除，中间的空格和tab不会
传空格或者tab参数，子串传仍然会把字符串开头和结尾的无论空格还是tab都一并删除
当传入的参数是其他参数时，字符串开头结尾不是该参数字符串，则没有任何效果
但是如果字符串的开头和结尾是其他字符串，并且传入的参数也是这个字符串，那么会将字符串开头和结尾的参数串全部清掉，无论有多少个。但是区分大小写。
例如，下面的例子：
line2='haaaaahhaaaaaaahHhhh'
print '*'+line2.strip('h')+'*'
结果输出：
*aaaaahhaaaaaaahH*