python统计日志ip访问数脚本

    import re  
    tudou@Gyyx  
    f=open("/tmp/a.log","r")  
    arr={}  
    lines = f.readlines()  
    for line in lines:  
        ipaddress=re.compile(r'^#(((2[0-4]\d|25[0-5]|[01]?\d\d?)\.){3}(2[0-4]\d|25[0-5]|[01]?\d\d?))')  
        match=ipaddress.match(line)  
        if match:  
            ip = match.group(1)  
            if(arr.has_key(ip)):  
                arr[ip]+=1  
            else:  
                arr.setdefault(ip,1)  
              
    f.close()  
    for key in arr:  
        print key+"->"+str(arr[key])  

日志格式为：

 #111.172.249.84 - - [12/Dec/2011:05:33:36 +0800] "GET /images/i/goTop.png HTTP/1.0" 200 486 "#/" "Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.1; Trident/5.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; .NET4.0C; .NET4.0E)"  
#111.172.249.84 - - [12/Dec/2011:05:33:36 +0800] "GET /images/i/goTop.png HTTP/1.0" 200 486 "#/" "Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.1; Trident/5.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; .NET4.0C; .NET4.0E)"  
#111.172.249.85 - - [12/Dec/2011:05:33:36 +0800] "GET /images/i/goTop.png HTTP/1.0" 200 486 "#/" "Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.1; Trident/5.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; .NET4.0C; .NET4.0E)"  
#111.172.249.86 - - [12/Dec/2011:05:33:36 +0800] "GET /images/i/goTop.png HTTP/1.0" 200 486 "#/" "Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.1; Trident/5.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; .NET4.0C; .NET4.0E)" 

输出结果

111.172.249.86->1

111.172.249.84->2

111.172.249.85->1

注释：python字段的setdefault用法为获取信息，如果获取不到的时候就按照他的参数设置该值

    >>> a={}  
    >>> a['key']='123'  
    >>> print (a)  
    {'key': '123'}  
    >>> print (a.setdefault('key','456'))  #显示a这个字典的'key'值的内容,因为字典有，所以不会去设置它  
    123  
      
    >>> print (a.setdefault('key1','456')) #显示a这个字典的'key1'值的内容，因为字典没有，所以设置为456了  
    456  
    >>> a  
    {'key1': '456', 'key': '123'}