python 内建函数
python 内建函数
列表：a.append a.count a.extend a.index a.insert a.pop a.remove a.reverse a.sort
a = [1, 3, 3, 2]
1. a.append L.append(object) -- append object to end
In [6]:a.append('qing') 添加一个对象（字符串，字典，元组等），每次只能添加一个值
In [8]: a
Out[8]: [1, 3, 3, 2, 'qing']
2. a.count L.count(value) -> integer -- return number of occurrences of value
In [14]: a.count(3) 查看有没有‘3’ 这个值以及数量
Out[14]: 2
3. a.extend L.extend(iterable) -- extend list by appending elements from the iterable
In [23]: a.extend('qing') 将字符串拆封成单个的字符串
In [24]: a
Out[24]: [1, 3, 3, 2, 'qing', 'q', 'i', 'n', 'g']
In [313]: a.extend(['why','not'])
Out[314]: [1, 2, 3, 'apple' 'why', 'not']
4. a.index L.index(value, [start, [stop]]) -> integer -- return first index of value.
Raises ValueError if the value is not present.
In [35]: a
Out[35]: [1, 3, 3, 2, 'qing', 'q', 'i', 'n', 'g']
In [36]: a.index('qing') 查看字符串qing 所在的位置，从0开始计数，返回第一个查询到的值
Out[36]: 4
5. a.insert L.insert(index, object) -- insert object before index
Out[44]: [1, 3, 3, 2, 'qing', 'q', 'i', 'n', 'g']
In [46]: a.insert(1,'liang') 在第二个位置插入字符串liang
Out[47]: [1, 'liang', 3, 3, 2, 'qing', 'q', 'i', 'n', 'g']
6 a.pop L.pop([index]) -> item -- remove and return item at index (default last).
Raises IndexError if list is empty or index is out of range.
In [55]: a
Out[55]: [1, 'liang', 3, 3, 2, 'qing', 'q', 'i', 'n']
In [56]: a.pop() 按位置删除列表， 为空 ，默认删除最后一个参数
Out[56]: 'n'
In [58]: a.pop(-1) -1 为倒数第一个， -2倒数第二个， 正数从0开始
Out[58]: 'i'
In [59]: a.pop(2)
Out[59]: 3
7. a.remove L.remove(value) -- remove first occurrence of value.
Raises ValueError if the value is not present.
In [70]: a
Out[70]: [1, 'liang', 2]
In [71]: a.remove('liang') 按列表中的内容删除
In [72]: a
Out[72]: [1, 2]
8. a.reverse L.reverse() -- reverse *IN PLACE*
In [79]: a
Out[79]: [1, 2, 'liang', 'ming']
In [81]: a.reverse() 将字符串倒着排序
In [82]: a
Out[82]: ['ming', 'liang', 2, 1]
9. a.sort L.sort(cmp=None, key=None, reverse=False) -- stable sort *IN PLACE*;
cmp(x, y) -> -1, 0, 1
In [100]: a
Out[100]: [1, 2, 'liang', 'ming', 'apple']
In [101]: a.sort() 按1234，abcd排序 ，数字优先
In [102]: a
Out[102]: [1, 2, 'apple', 'liang', 'ming']
字典；
qing.clear qing.fromkeys qing.has_key qing.iteritems qing.itervalues qing.pop qing.setdefault qing.values qing.viewkeys
qing.copy qing.get qing.items qing.iterkeys qing.keys qing.popitem qing.update qing.viewitems qing.viewvalues
qing = {'liang':'ming','qing':'fanqin' }
1. qing.clear D.clear() -> None. Remove all items from D.
In [130]: qing
Out[130]: {'liang': 'ming', 'qing': 'fanqin'}
In [133]: qing.clear() 清空字典
In [134]: qing
Out[134]: {}
2. qing.fromkeys dict.fromkeys(S[,v]) -> New dict with keys from S and values equal to v.
函数用于创建一个新字典，以序列S中元素做字典的键，value为字典所有键对应的初始值。
In [152]: a
Out[152]: [1, 2, 3, 'apple', 'big', 'hi', 'liang', 'ming']
In [153]: qing
Out[153]: {'liang': 'ming', 'qing': 'fanqin'}
In [155]: qing.fromkeys(a) 将列表a的参数当做字典的key，没有指定 ， 默认value所以值为none
Out[155]:
{1: None, 2: None, 3: None, 'apple': None，'big': None, 'hi': None, 'liang': None, 'ming': None}
In [156]: qing.fromkeys(a,10)
Out[156]: {1: 10, 2: 10, 3: 10,'apple': 10,'big': 10，'hi': 10,'liang': 10,'ming': 10}
3. qing.has_key D.has_key(k) -> True if D has a key k, else False
In [159]: qing
Out[159]: {'liang': 'ming', 'qing': 'fanqin'}
In [161]: qing.has_key('liang') 判断字典中是否有key--liang 若有返回True 否则 False
Out[161]: True
4. qing.pop D.pop(k[,d]) -> v, remove specified key and return the corresponding value.
If key is not found, d is returned if given, otherwise KeyError is raised
In [167]: qing
Out[167]: {'liang': 'ming', 'qing': 'fanqin'}
In [168]: qing.pop('liang') 删除字典中的key，value， 因为key值唯一，所以不用写value
Out[168]: 'ming'
In [169]: qing
Out[169]: {'qing': 'fanqin'}
5. qing.setdefault D.setdefault(k[,d]) -> D.get(k,d), also set D[k]=d if k not in D
In [169]: qing
Out[169]: {'qing': 'fanqin'}
In [174]: qing.setdefault('qing') 如果存在qing这个key 则直接返回结果
Out[174]: 'fanqin'
In [175]: qing.setdefault('liang') 如果不存在liang这个key 则将liang 当做key，直接添加到字典中，若不指定value，则为None
In [176]: qing
Out[176]: {'liang': None, 'missyou': None, 'qing': 'fanqin'}
In [182]: qing.setdefault('qin','sf') 若不存在qing这个key 这将key，value直接插入到字典中
Out[183]: {'liang': None, 'missyou': None, 'qin': 'sf', 'qing': 'fanqin'}
6. qing.values() D.values() -> list of D's values
In [187]: qing.values() 列出字典qing中所有的value值
Out[187]: ['ele', 'fanqin', 'ming']
7. qing.keys() D.keys() -> list of D's keys
In [193]: qing.keys() 列出所有的key值
Out[193]: ['ting', 'qing', 'liang']
8. qing.items() D.items() -> list of D's (key, value) pairs, as 2-tuples
In [214]: qing.items() 以元组的形式列出字典中所有的内容
Out[214]: [('ting', 'ele'), ('qing', 'fanqin'), ('liang', 'ming')]
9. qing.viewvalues D.viewvalues() -> an object providing a view on D's values
In [215]: qing.viewvalues()
Out[215]: dict_values(['ele', 'fanqin', 'ming'])
10. qing.viewkeys D.viewkeys() -> a set-like object providing a view on D's keys
In [218]: qing.viewkeys()
Out[218]: dict_keys(['ting', 'qing', 'liang']
11. qing.viewitems() D.viewitems() -> a set-like object providing a view on D's items
In [220]: qing.viewitems()
Out[220]: dict_items([('ting', 'ele'), ('qing', 'fanqin'), ('liang', 'ming')])
12. qing.copy D.copy() -> a shallow copy of D
In [224]: ming=qing.copy() 复制字典
In [225]: ming
Out[225]: {'liang': 'ming', 'qing': 'fanqin', 'ting': 'ele'}
13. qing.get D.get(k[,d]) -> D[k] if k in D, else d. d defaults to None.
In [227]: qing
Out[227]: {'liang': 'ming', 'qing': 'fanqin', 'ting': 'ele'}
In [228]: qing.get('ting') 查询ting 对应的value值
Out[228]: 'ele'
In [233]: qing.get('what') 当key不存在是 没有返回或者为none
In [234]:
14. qing.popitem D.popitem() -> (k, v), remove and return some (key, value) pair as a 2-tuple; but raise KeyError if D is empty.
In [240]: qing
Out[240]: {'liang': 'ming', 'qing': 'fanqin', 'ting': 'ele'} In
In [241]: qing.popitem() 为空， 默认删除最后一个
Out[241]: ('ting', 'ele')
15. qing.update D.update([E, ]**F) -> None. Update D from dict/iterable E and F.
If E present and has a .keys() method, does: for k in E: D[k] = E[k]
If E present and lacks .keys() method, does: for (k, v) in E: D[k] = v
In either case, this is followed by: for k in F: D[k] = F[k]
In [261]: qing
Out[261]: {'liang': 'ming', 'qing': 'fanqin'}
In [262]: ting = {'why':'boring'}
In [263]: qing.update(ting) 字典qing中没有字典ting的key值时 直接添加
In [264]: qing
Out[264]: {'liang': 'ming', 'qing': 'fanqin', 'why': 'boring'}
In [274]: qing
Out[274]: {'liang': 'ming', 'qing': 'fanqin', 'why': 'boring'}
In [275]: ting
Out[275]: {'why': 'ele'}
In [276]: qing.update(ting)
In [277]: qing 字典qing中有字典ting的key值时 ， 直接修改
Out[277]: {'liang': 'ming', 'qing': 'fanqin', 'why': 'ele'}
元组：
1. ting.count T.count(value) -> integer -- return number of occurrences of value
In [298]: ting = ('a','b','c')
In [303]: ting.count('b')
Out[303]: 1
2. ting.index T.index(value, [start, [stop]]) -> integer -- return first index of value
In [306]: ting.index('c')
Out[306]: 2
字符串：
a.isdigit( a.rsplit(
a.islower( a.rstrip(
a.isspace( a.split(
a.capitalize( a.istitle( a.splitlines(
a.center( a.isupper( a.startswith(
a.count( a.join( a.strip(
a.decode( a.ljust( a.swapcase(
a.encode( a.lower( a.title(
a.endswith( a.lstrip( a.translate(
a.expandtabs( a.partition( a.upper(
a.find( a.replace( a.zfill(
a.format( a.rfind(
a.index( a.rindex(
a.isalnum( a.rjust(
a.isalpha( a.rpartition(
qing = 'lot of Yihan For You
1. str.count() //返回该字符串中某个子串出现的次数
>>> qing
'lot of Yihan For You'
>>> qing.count('o')
4
2. str.find() //返回某个子串出现在该字符串的起始位置
>>> qing.find("Y")
7
3. str.lower() //将该字符串全部转化为小写
>>> qing.lower()
'lot of yihan for you'
4. str.upper() //转为大写
>>> qing.upper()
'LOT OF YIHAN FOR YOU'
5. len(str) //返回字符串长度
>>> len(qing)
20
6.S.swapcase() #大小写互换
>>> qing.swapcase()
'LOT OF yIHAN fOR yOU'
7. >>> qing.capitalize() 将首字母大写
'Lot of yihan for you
8. name.split 将字符串拆分成列表的形式， 默认为空格
>>> name.split("'")
['what', 's your name']
9. str.join
>>> ming
['what', 's your name']
>>> '|'.join(ming)
'what|s your name'
>>>
文件 file
f = file('/qing/qing.txt')
f.close( f.isatty( f.readinto( f.truncate(
f.closed f.mode f.readline( f.write(
f.encoding f.name f.readlines( f.writelines(
f.errors f.newlines f.seek( f.xreadlines(
f.fileno( f.next( f.softspace f.flush(
f.read( f.tell(
1. f.read() 将整个文件读出来，并以字符串的形式显示
'lalalani dong de \nni dong de \nsdfsd\nsfsfafsdfasfasdfsdfssssssssssssss\nllll\n'
2. f.readlines() 将整个文件读出来， 并以列表的形式显示
['lalalani dong de \n', 'ni dong de \n', 'sdfsd\n', 'sfsfafsdfasfasdfsdfssssssssssssss\n', 'llll\n']
3. f.readline() 一行一行读，以字符串的形式显示
>>> f.readline()
'lalalani dong de \n'
>>> f.readline()
'ni dong de \n'
4. f.mode
'r'
5. f.name
'/qing/qing.txt'
6. f.next() 同f.readline()一样， 只是在读取到最后一行以后会报错，而readline（）不会报错
'llll\n'
f.next()
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
StopIteration
>>> f.readline()
''
7. >>> f.seek(0) 跳到文件的指定字符位置，一般用作跳到文件开头的作用
>>> f.tell() 显示文件当前位置
0
>>> f.seek(10)
8. f.truncate() 删除字符，与当前位置无关，以开始位置计数， 默认字节
f = file('/qing/qing.txt','r+') 以读写模式打开
f.readlines()
['lalalani dong de \n', 'ni dong de \n', 'sdfsd\n', 'sfsfafsdfasfasdfsdfssssssssssssss\n', 'llll\n']
>>> f.truncate(20)
f.readlines()
['lalalani dong de \n', 'ni']
9.
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