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Python commonly used built-in sequence structures (lists, tuples, dictionaries) study notes

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Release: 2016-07-22 08:56:26
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列表与元组
列表用大括号[]表示,元组用圆括号()表示。
列表可以修改,字符串与元组不可修改。
元组的分片还是元组,列表的分片还是列表。

1.列表方法:

name=["zhang3","li4","wang5"]
name.append("gou6") #添加项
name.remove("gou6") #移除第一个匹配项,也可用del name[3]来移除
name.insert(3,"gou6") #插入项
name.index("gou6") #找出第一个匹配项的位置
name.extend(["gou6","xuan7"]) #扩展
name.pop(0) #返回列表的第一项值并从列表中删除之
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2.列表函数:

>>> a=list("hi guys") #把字符串转换为列表
>>> print a
['h', 'i', ' ', 'g', 'u', 'y', 's']
>>> ''.join(a)  #把列表还原成字符串
'hi guys'
>>> max(a) #取得列表的最大元素
'y'
>>> len(a) #取得列表长度
7
>>> min(a) #取得最小元素
' '
>>> tuple(a) #将列表转换为元组
('h', 'i', ' ', 'g', 'u', 'y', 's')
>>> sorted(a) #将列表元素排序
[' ', 'g', 'h', 'i', 's', 'u', 'y']

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3.列表遍历:

A,使用for语句遍历

for each_item in name:
   print(each_item)
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B,使用while语句遍历

i=0
while i < len(name):
   print(name[i])
   i += 1
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4.成员资格1:

>>> sub="hello, you are a bear"
>>> "bear" in sub
True
>>> "y" in sub
True
>>> raw_input("what's your name&#63;") in sub
what's your name&#63;bear
True

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5.成员资格2:

database=[
["zhang3","0111"],
["li4","0112"],
["wang5","0113"]
]
username=raw_input("what's your user name&#63;")
id=raw_input("what's your id&#63;")
if [username,id] in database: print "access granted"

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6.找出10以内的整数

s = [x for x in range(0, 10) if x % 2 == 0]
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7.生成九九乘法表

s = [(x, y, x*y) for x in range(1, 10) for y in range(1,10) if x>=y]
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字符串

1.获取字符串

name=raw_input("what's your name&#63;")
      print "Hello," + name + ".welcome to us"
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注意:Pyhton3.x版本取消了raw_input,统一使用input
输出值:

print name + repr(x)
#str用于把值转换为合理的字符串,repr创建一个字符串,返回值的字符串形式
#str是一种类型(和int一样),repr是函数

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2.换行符用\n表示
原始字符串,以字符串前加一个r即可,如

print r"c:\nowindows\no"
path="c:\nowindows\no"; print repr(path)
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3.Unicode字符串

 print u"redhat"
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注意:Pyhton3.x版本所有字符串都是unicode字符串
定义字符串时,双引号和单引号都是可以用的,只不过用单引号的时候可以在字符串里面使用双引号
布尔值:

>>> bool('i love you')
True
>>> bool(42)
True
>>> bool(1)
True
>>> bool('0')
True
>>> bool(0)
False
>>> bool('')
False
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4.字符串方法

>>> tag="<a href=http://www.baidu.com>baidu indexpage</a>"
>>> print tag[8:28] #字符串分片
http://www.baidu.com
>>> print tag[29:-4] #字符串分片
baidu indexpage
>>> tag.replace("www.baidu.com","home.sina.com") #字符串替换
'<a href=http://home.sina.com>baidu indexpage</a>'

>>> dirs=["","usr","bin","env"]
>>> "/".join(dirs)  #将列表拼接成字符串
'/usr/bin/env'
>>> print ("C:" + "\\".join(dirs))
C:\usr\bin\env

>>> path="/usr/bin/env"
>>> path.split("/") #将字符串分割成列表
['', 'usr', 'bin', 'env']

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5.其它字符串方法

>>> s=' I Love you!  '
>>> s.lower() #转换字符串的小写
' i love you!  '
>>> s.upper() #转换字符串的大写
' I LOVE YOU!  '
>>> s.title() #换换字符串为标题(所有单词首字母大写)
' I Love You!  '
>>> s.islower() #判断字符串是否为小写(也可判断大写和标题)
False
>>> s.strip()  #去除首尾空格,lstrip去除左边空格,rstrip去除右边空格
'I Love you!'
>>> word=s.split() #分割
>>> word
['I', 'Love', 'you!']
>>> '::'.join(word) #合并
'I::Love::you!'
>>> s.count('o') #统计出现次数
2
>>> s.find('you') #查找位置,如果找不到,则返回-1
9
>>> s.startswith('python')
False
>>> s.replace('you','yours')
' I Love yours!  '
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