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"