常用的Python代码段

过滤列表

 #filter out empty strings in a sting list
 list = [x for x in list if x.strip()!='']

一行一行地读文件

 with open("/path/to/file") as f:
     for line in f:
         print line

逐行写文件

 f = open("/path/tofile", 'w')
 for e in aList:
     f.write(e + "\n")f.close()

正则匹配查找

 sentence = "this is a test, not testing."
 it = re.finditer('\\btest\\b', sentence)
 for match in it:
     print "match position: " + str(match.start()) +"-"+ str(match.end())

正则匹配搜索

 m = re.search('\d+-\d+', line) #search 123-123 like strings
 if m:
     current = m.group(0)

查询数据库

 db = MySQLdb.connect("localhost","username","password","dbname")
 cursor = db.cursor()
 sql = "select Column1,Column2 from Table1"
 cursor.execute(sql)
 results = cursor.fetchall()
 for row in results:
     print row[0]+row[1] db.close()

用指定字符连接列表

 theList = ["a","b","c"]
 joinedString = ",".join(theList)

去除重复元素

 targetList = list(set(targetList))

在一列字符串中去除空字符串

 targetList = [v for v in targetList if not v.strip()=='']
 # or
 targetList = filter(lambda x: len(x)>0, targetList)

将一个列表连接到另一个列表后面

 anotherList.extend(aList)

遍历一个字典

 for k,v in aDict.iteritems():
     print k+v

检查一列字符串中是否有任何一个出现在指定字符串里

 if any(x in targetString for x in aList):
     print "true"