python检查字符串是否是正确ISBN的方法

本文实例讲述了python检查字符串是否是正确ISBN的方法。分享给大家供大家参考。具体实现方法如下：

    def isISBN(isbn): 
      """Checks if the passed string is a valid ISBN number.""" 
      if len(isbn) != 10 or not isbn[:9].isdigit(): 
        return False 
      if not (isbn[9].isdigit() or isbn[9].lower() == "x"): 
        return False 
      tot = sum((10 - i) * int(c) for i, c in enumerate(isbn[:-1])) 
      checksum = (11 - tot % 11) % 11 
      if isbn[9] == 'X' or isbn[9] == 'x': 
        return checksum == 10 
      else: 
        return checksum == int(isbn[9]) 
    ok = """031234161X 0525949488 076360013X 0671027360 0803612079 
        0307263118 0684856093 0767916565 0071392319 1400032806 0765305240""" 
    for code in ok.split(): 
      assert isISBN(code) 
    bad = """0312341613 052594948X 0763600138 0671027364 080361207X 0307263110 
         0684856092 0767916567 0071392318 1400032801 0765305241 031234161 
         076530Y241 068485609Y""" 
    for code in bad.split(): 
      assert not isISBN(code) 
    print "Tests of isISBN()passed." 

希望本文所述对大家的Python程序设计有所帮助。