python拷贝文件函数_Python Set集合,函数,深入拷贝,浅入拷贝,文件处理
1、Set基本數(shù)據(jù)類型
a、set集合,是一個無序且不重復(fù)的元素集合
classset(object):"""set() -> new empty set object
set(iterable) -> new set object
Build an unordered collection of unique elements."""
def add(self, *args, **kwargs): #real signature unknown
"""Add an element to a set,添加元素
This has no effect if the element is already present."""
pass
def clear(self, *args, **kwargs): #real signature unknown
"""Remove all elements from this set. 清楚內(nèi)容"""
pass
def copy(self, *args, **kwargs): #real signature unknown
"""Return a shallow copy of a set. 淺拷貝"""
pass
def difference(self, *args, **kwargs): #real signature unknown
"""Return the difference of two or more sets as a new set. A中存在,B中不存在
(i.e. all elements that are in this set but not the others.)"""
pass
def difference_update(self, *args, **kwargs): #real signature unknown
"""Remove all elements of another set from this set. 從當(dāng)前集合中刪除和B中相同的元素"""
pass
def discard(self, *args, **kwargs): #real signature unknown
"""Remove an element from a set if it is a member.
If the element is not a member, do nothing. 移除指定元素,不存在不保錯"""
pass
def intersection(self, *args, **kwargs): #real signature unknown
"""Return the intersection of two sets as a new set. 交集
(i.e. all elements that are in both sets.)"""
pass
def intersection_update(self, *args, **kwargs): #real signature unknown
"""Update a set with the intersection of itself and another. 取交集并更更新到A中"""
pass
def isdisjoint(self, *args, **kwargs): #real signature unknown
"""Return True if two sets have a null intersection. 如果沒有交集,返回True,否則返回False"""
pass
def issubset(self, *args, **kwargs): #real signature unknown
"""Report whether another set contains this set. 是否是子序列"""
pass
def issuperset(self, *args, **kwargs): #real signature unknown
"""Report whether this set contains another set. 是否是父序列"""
pass
def pop(self, *args, **kwargs): #real signature unknown
"""Remove and return an arbitrary set element.
Raises KeyError if the set is empty. 移除元素"""
pass
def remove(self, *args, **kwargs): #real signature unknown
"""Remove an element from a set; it must be a member.
If the element is not a member, raise a KeyError. 移除指定元素,不存在保錯"""
pass
def symmetric_difference(self, *args, **kwargs): #real signature unknown
"""Return the symmetric difference of two sets as a new set. 對稱交集
(i.e. all elements that are in exactly one of the sets.)"""
pass
def symmetric_difference_update(self, *args, **kwargs): #real signature unknown
"""Update a set with the symmetric difference of itself and another. 對稱交集,并更新到a中"""
pass
def union(self, *args, **kwargs): #real signature unknown
"""Return the union of sets as a new set. 并集
(i.e. all elements that are in either set.)"""
pass
def update(self, *args, **kwargs): #real signature unknown
"""Update a set with the union of itself and others. 更新"""
pass
set
b、數(shù)據(jù)類型模塊舉例
se = {11,22,33,44,55}
be = {44,55,66,77,88}
# se.add(66)
# print(se) #添加元素,不能直接打印!
#
#
#
# se.clear()
# print(se) #清除se集合里面所有的值,不能清除單個
#
#
#
# ce=be.difference(se) #se中存在,be中不存在的值,必須賦值給一個新的變量
# print(ce)
#
#
# se.difference_update(be)
# print(se) #在se中刪除和be相同的值,不能賦值給一個新的變量,先輸入轉(zhuǎn)換,然后打印,也不能直接打印!
# se.discard(11)
# print(se) #移除指定元素,移除不存在的時候,不會報錯
# se.remove(11)
# print(se) #移除指定的元素,移除不存在的會報錯
# se.pop()
# print(se) #移除隨機(jī)的元素
#
#
# ret=se.pop()
# print(ret) #移除元素,并且可以把移除的元素賦值給另一個變量
# ce = se.intersection(be)
# print(ce) #取出兩個集合的交集(相同的元素)
# se.intersection_update(be)
# print(se) #取出兩個集合的交集,并更新到se集合中
# ret = se.isdisjoint(be)
# print(ret) #判斷兩個集合之間又沒有交集,如果有交集返回False,沒有返回True
# ret=se.issubset(be)
# print(ret) #判斷se是否是be集合的子序列,如果是返回True,不是返回Flase
# ret = se.issuperset(be)
# print(ret) #判斷se是不是be集合的父序列,如果是返回True,不是返回Flase
# ret=se.symmetric_difference(be)
# print(ret) #對稱交集,取出除了不相同的元素
# se.symmetric_difference_update(be)
# print(se) #對稱交集,取出不相同的元素并更新到se集合中
# ret = se.union(be)
# print(ret) #并集,把兩個元素集合并在一個新的變量中
2、深淺拷貝
a、數(shù)字和字符串
對于 數(shù)字 和 字符串 而言,賦值、淺拷貝和深拷貝無意義,因?yàn)槠溆肋h(yuǎn)指向同一個內(nèi)存地址。
import copy
# ######### 數(shù)字、字符串 #########
n1 = 123
# n1 = "i am alex age 10"
print(id(n1))
# ## 賦值 ##
n2 = n1
print(id(n2))
# ## 淺拷貝 ##
n2 = copy.copy(n1)
print(id(n2))
# ## 深拷貝 ##
n3 = copy.deepcopy(n1)
print(id(n3))
b、其他基本數(shù)據(jù)類型
對于字典、元祖、列表 而言,進(jìn)行賦值、淺拷貝和深拷貝時,其內(nèi)存地址的變化是不同的。
1、賦值
賦值,只是創(chuàng)建一個變量,該變量指向原來內(nèi)存地址,如:
n1 = {"k1": "zhangyanlin", "k2": 123, "k3": ["Aylin", 456]}
n2 = n1
2、淺拷貝
淺拷貝,在內(nèi)存中只額外創(chuàng)建第一層數(shù)據(jù)
import copy
n1 = {"k1": "zhangyanlin", "k2": 123, "k3": ["aylin", 456]}
n3 = copy.copy(n1)
3、深拷貝
深拷貝,在內(nèi)存中將所有的數(shù)據(jù)重新創(chuàng)建一份(排除最后一層,即:python內(nèi)部對字符串和數(shù)字的優(yōu)化)
3、函數(shù)
函數(shù)式:將某功能代碼封裝到函數(shù)中,日后便無需重復(fù)編寫,僅調(diào)用函數(shù)即可
面向?qū)ο?#xff1a;對函數(shù)進(jìn)行分類和封裝,讓開發(fā)“更快更好更強(qiáng)...
函數(shù)傳參數(shù)傳的是引用
.函數(shù)的定義主要有如下要點(diǎn):
def:表示函數(shù)的關(guān)鍵字
函數(shù)名:函數(shù)的名稱,日后根據(jù)函數(shù)名調(diào)用函數(shù)
函數(shù)體:函數(shù)中進(jìn)行一系列的邏輯計算,如:發(fā)送郵件、計算出 [11,22,38,888,2]中的最大數(shù)等...
參數(shù):為函數(shù)體提供數(shù)據(jù)
返回值:當(dāng)函數(shù)執(zhí)行完畢后,可以給調(diào)用者返回數(shù)據(jù)。
1、返回值
函數(shù)是一個功能塊,該功能到底執(zhí)行成功與否,需要通過返回值來告知調(diào)用者。
以上要點(diǎn)中,比較重要有參數(shù)和返回值:
def 發(fā)送短信():
發(fā)送短信的代碼...
if 發(fā)送成功:
return True
else:
return False
while True:
# 每次執(zhí)行發(fā)送短信函數(shù),都會將返回值自動賦值給result
# 之后,可以根據(jù)result來寫日志,或重發(fā)等操作
result = 發(fā)送短信()
if result == False:
短信發(fā)送失敗...
函數(shù)的有三中不同的參數(shù):
普通參數(shù)
# ######### 定義函數(shù) #########
# name 叫做函數(shù)func的形式參數(shù),簡稱:形參
def func(name):
print name
# ######### 執(zhí)行函數(shù) #########
# 'zhangyanlin' 叫做函數(shù)func的實(shí)際參數(shù),簡稱:實(shí)參
func('zhangyanlin')
默認(rèn)參數(shù)
def func(name, age = 18):
print "%s:%s" %(name,age)
# 指定參數(shù)
func('zhangyanlin', 19)
# 使用默認(rèn)參數(shù)
func('nick')
注:默認(rèn)參數(shù)需要放在參數(shù)列表最后
動態(tài)參數(shù)
def func(*args):
print args
# 執(zhí)行方式一
func(11,33,4,4454,5)
# 執(zhí)行方式二
li = [11,2,2,3,3,4,54]
func(*li)
def func(**kwargs):
print args
# 執(zhí)行方式一
func(name='wupeiqi',age=18)
# 執(zhí)行方式二
li = {'name':'wupeiqi', age:18, 'gender':'male'}
func(**li)
def func(*args, **kwargs):
print args
print kwargs
郵件實(shí)例:
def email(p,j,k):
import smtplib
from email.mime.text import MIMEText
from email.utils import formataddr
set = True
try:
msg = MIMEText('j', 'plain', 'utf-8') #j 郵件內(nèi)容
msg['From'] = formataddr(["武沛齊",'wptawy@126.com'])
msg['To'] = formataddr(["走人",'424662508@qq.com'])
msg['Subject'] = "k" #k主題
server = smtplib.SMTP("smtp.126.com", 25)
server.login("wptawy@126.com", "WW.3945.59")
server.sendmail('wptawy@126.com', [p], msg.as_string())
server.quit()
except:
set = False
return True
formmail = input("請你輸入收件人郵箱:")
zhuti = input("請您輸入郵件主題:")
neirong = input("請您輸入郵件內(nèi)容:")
aa=email(formmail,neirong,zhuti)
if aa:
print("郵件發(fā)送成功!")
else:
print("郵件發(fā)送失敗!")
2、 內(nèi)置函數(shù)
# abs絕對值
# i = abs(-123)
# print(i) #返回123,絕對值
# #all,循環(huán)參數(shù),如果每個元素為真,那么all返回的為真,有一個為假返回的就是假的
# a = all((None,123,456,False))
# print(a) #返回的為假的,證明中間有False值
#
# #所有的假值有
# #0,None,空值
#
# #any 只要之前有一個是真的,返回的就是真
# b = any([11,False])
# print(b)
#ascii,去指定對象的類中找__repr__,獲取返回值
# #ascii函數(shù)
# class Foo:
# def __repr__(self):
# return "zhangyanlin"
# obj =Foo()
# r = ascii(obj)
# print(r)
# 布爾值返回真或假
# print(bool(1))
# print(bool(0))
# #bin二進(jìn)制
# r = bin(123)
# print(r)
# #oct八進(jìn)制
# r = oct(123)
# print(r)
# #int十進(jìn)制
# r = int(123)
# print(r)
# #hex十六進(jìn)制
# r = hex(123)
# print(r)
# #二進(jìn)制轉(zhuǎn)十進(jìn)制
# i= int("0b11",base=2)
# print(i)
# #八進(jìn)制轉(zhuǎn)十進(jìn)制
# i= int("11",base=8)
# print(i)
# #十六進(jìn)制轉(zhuǎn)十進(jìn)制
# i = int("0xe",base=16)
# print(i)
# #數(shù)字代表字母
# c = chr(66)
# print(c)
# #字母代表數(shù)字
# c = ord("a")
# print(c)
#bytes, 字節(jié)
#字節(jié)和字符串的轉(zhuǎn)換
# a = bytes("zhangyanlin",encoding="utf-8")
# print(a)
#bytearray 字節(jié)列表
#chr(),把數(shù)字轉(zhuǎn)換成字母,只適用于ascii碼
# a = chr(65)
# print(a)
#ord(),把字母轉(zhuǎn)換成數(shù)字,只適用于ascii碼
# a = ord("a")
# print(a)
#callable表示一個對象是否可執(zhí)行
# def f1(): #看這個函數(shù)能不能執(zhí)行,能發(fā)揮True
# return 123
# f1()
# r = callable(f1)
# print(r)
#dir,查看一個類里面存在的功能
# li = []
# print(dir(li))
# help(list)
#divmod(),#分頁的時候使用
# a = 10/3
# r = divmod(10,3)
# print(r)
#compile編譯, 把字符串轉(zhuǎn)移成python可執(zhí)行的代碼,知道就行
#eval(),簡單的表達(dá)式,可以給算出來
# b = eval("a + 69" , {"a":99}) #a可以通過字典聲明變量去寫入
# print(b)
#exec,不會返回值,直接輸出結(jié)果
# exec("for i in range(10):print(i)")
# filter對于序列中的元素進(jìn)行篩選,最終獲取符合條件的序列(需要循環(huán))
# def f1(x):
# if x >22:
# return True
# else:
# return False
#
# ret = filter(f1,[11,22,33,44,55])
# for i in ret:
# print(i)
# ret = filter(lambda x: x > 22, [11, 22, 33, 44, 55, 66, 77])
# for i in ret:
# print(i)
#map(函數(shù),可以迭代的對象,讓元素統(tǒng)一操作)
# def f1(x):
# return x+123
#
# # li = [11,22,33,44,55,66]
# # ret = map(f1,li)
# print(ret)
# for i in ret:
# print(i)
#
# ret = map(lambda x: x + 100 if x%2==1 else x, [11, 22, 33, 44])
# print(ret)
# for i in ret:
# print(i)
#globals()獲取當(dāng)前所有的全局變量
#locals()獲取當(dāng)前所有的局部變量
# ret = "kaszhfiusdhf"
# def fu1():
# name = 123
# print(locals())
# print(globals())
#
# fu1()
#hash 對key的優(yōu)化,相當(dāng)于給輸出一種哈希值
# li = "sdglgmdgongoaerngonaeorgnienrg"
# print(hash(li))
#isinstance()判斷是不是一個類型
# li = [11,22]
# ret = isinstance(li,list)
# print(ret)
#iter創(chuàng)建一個可以被迭代的元素
# obj = iter([11,22,33,44])
# print(obj)
# #next,取下一個值,一個變量里的值可以一直往下取,直到?jīng)]有就報錯
# ret = next(obj)
#max()取最大的值
# li = [11,22,33,44]
# ret = max(li)
# print(ret)
#min()取最小值
# li = [11,22,33,44]
# ret = min(li)
# print(ret)
#求一個數(shù)字的多少次方
# ret = pow(2,10)
# print(ret)
#reversed反轉(zhuǎn)
# a = [11,22,33,44]
# b = reversed(a)
# for i in b:
# print(i)
#round 四舍五入
# ret = round(4.8)
# print(ret)
#sum求和
# ret = sum((11,22,33,44))
# print(ret)
#zip,1 1對應(yīng)
# li1 = [11,22,33,44,55]
# li2 = [99,88,77,66,89]
# dic = dict(zip(li1,li2))
# print(dic)
#sorted 排序
# li = ["1","2sdg;l","57","a","b","A","中國人"]
# lis = sorted(li)
# print(lis)
# for i in lis:
# print(bytes(i,encoding="utf-8"))
# #隨機(jī)生成6位驗(yàn)證碼
# import random
# temp = ''
# for i in range(6):
# num = random.randrange(0,4)
# if num ==3 or num ==1:
# rad1 = random.randrange(0,10)
# temp+=str(rad1)
# else:
# rad2 = random.randrange(65,91)
# c1 = chr(rad2)
# temp+=c1
# print(temp)
4、文件處理
a、打開文件
name = open('文件路徑', '模式')
打開文件時,需要指定文件路徑和以何等方式打開文件,打開后,即可獲取該文件句柄,日后通過此文件句柄對該文件操作。
打開文件的模式有:
r ,只讀模式【默認(rèn)】
w,只寫模式【不可讀;不存在則創(chuàng)建;存在則清空內(nèi)容;】
x, 只寫模式【不可讀;不存在則創(chuàng)建,存在則報錯】
a, 追加模式【不可讀; ? 不存在則創(chuàng)建;存在則只追加內(nèi)容;】
"+" 表示可以同時讀寫某個文件
r+, 讀寫【可讀,可寫】
w+,寫讀【可讀,可寫】
x+ ,寫讀【可讀,可寫】
a+, 寫讀【可讀,可寫】
"b"表示以字節(jié)的方式操作
rb ?或 r+b
wb 或 w+b
xb?或 w+b
ab?或 a+b
注:以b方式打開時,讀取到的內(nèi)容是字節(jié)類型,寫入時也需要提供字節(jié)類型
例:
#普通方式打開
# ====pythobnn內(nèi)部將二進(jìn)制轉(zhuǎn)換成字符串,通過字符串操作
#二進(jìn)制打開方式
#用戶自己操作把字符串轉(zhuǎn)成二進(jìn)制,然后讓電腦識別
# 1. 只讀模式,r
# a = open("1.log","r") #打開1.log,賦予只讀的權(quán)限
# ret = a.read() #讀取文件
# a.close() #退出文件
# print(ret) #打印文件內(nèi)容
#2.只寫模式,w, 如果不存在會創(chuàng)建文件,存在則清空內(nèi)容
# a = open("3.log","w")
# a.write("sdfhsuigfhuisg")
# a.close()
#3.只寫模式,x, 如果不存在會創(chuàng)建文件,存在則報錯
# a = open("4.log","x")
# a.write("12345678")
# a.close()
#4.追加模式,a,不可讀,不存在則創(chuàng)建文件,存在則會追加內(nèi)容
# a = open("4.log","a")
# a.write("asjfioshf")
# a.close()
# "b"表示處理二進(jìn)制文件(如:FTP發(fā)送上傳ISO鏡像文件,linux可忽略,windows處理二進(jìn)制文件時需標(biāo)注)
#5.只讀模式,rb,以字節(jié)方式打開,默認(rèn)打開是字節(jié)的方式
# a = open("2.log","rb") #二進(jìn)制方式讀取2.log文件
# date = a.read() #定義變量,讀文件
# a.close() #關(guān)閉文件
# print(date) #打印文件
# str_data = str(date, encoding="utf-8") #字節(jié)轉(zhuǎn)換成utf-8
# print(str_data) # 打印文件
#6.只寫模式,wb,
# a = open("2.log","wb") #打開文件2.log,可寫的模式
# date = "中國人" #定義字符串
# a.write(bytes(date , encoding="utf-8")) #轉(zhuǎn)換成字節(jié),方便計算機(jī)識別
# a.close() #關(guān)閉文件
# print(date) #打印出來
#7.只寫模式,xb,
# a = open("6.log","xb")
# date = "張巖林非常帥"
# # a.write("sakfdhisf") #字符串形式會報錯,計算機(jī)不識別,得轉(zhuǎn)換成字節(jié)
# a.write(bytes(date,encoding="utf-8"))
# a.close()
# print(date)
#8.追加模式,ab,
# a = open("5.log","ab")
# date = "!張巖林是個帥小伙子"
# a.write(bytes(date,encoding="utf-8"))
# a.close()
# print(date)
# #"+"表示具有讀寫的功能
# #9.r+,讀寫(可讀,可寫)
# a = open("5.log","r+",encoding="utf-8")
# print(a.tell()) #打開文件后觀看指針位置在第幾位,默認(rèn)在起始位置
#
# date = a.read() #第一次讀取,指針讀取到最后了,(可以加讀取的索引位置,3表示只看前三位)
# print(date)
#
# a.write("太帥了") #寫的時候會把指針調(diào)到最后去寫
#
# a.seek(0) #把指針放在第一位進(jìn)行第二次讀取
#
# date = a.read() #第二次讀取
# print(date)
# a.close()
#10.w+,寫讀,(可寫,可讀),先清空內(nèi)容,在寫之后需要把指針放在第一位才能讀
# a = open("5.log","w+",encoding="utf-8")
# a.write("張巖林") #清空內(nèi)容寫入“張巖林”
# a.seek(0) #把指針放在第一位
# date = a.read() #進(jìn)行讀取
# a.close() #退出文件
# print(date)
#11.x+,寫讀,(可寫,可讀),需要創(chuàng)建一個新文件,文件存在會報錯,在寫之后需要把指針放在第一位才能讀
# a = open("7.log","x+",encoding="utf-8")
# a.write("張巖林") #清空內(nèi)容寫入“張巖林”
# a.seek(0) #把指針放在第一位
# date = a.read() #進(jìn)行讀取
# a.close() #退出文件
# print(date)
#12.a+,寫讀,(可寫,可讀),打開文件的同時,指針已經(jīng)在最后了
# a = open("5.log","a+",encoding="utf-8")
# date = a.read() #第一次讀,沒數(shù)據(jù),因?yàn)橹羔樤谧詈?/p>
# print(date)
#
# a.write("張張") #往最后寫入 張
#
# a.seek(0) #把指針放在第一位,讓他進(jìn)行曲讀
# date = a.read()
# print(date)
#
# a.close()
b、操作操作
classTextIOWrapper(_TextIOBase):"""Character and line based layer over a BufferedIOBase object, buffer.
encoding gives the name of the encoding that the stream will be
decoded or encoded with. It defaults to locale.getpreferredencoding(False).
errors determines the strictness of encoding and decoding (see
help(codecs.Codec) or the documentation for codecs.register) and
defaults to "strict".
newline controls how line endings are handled. It can be None, '',
'\n', '\r', and '\r\n'. It works as follows:
* On input, if newline is None, universal newlines mode is
enabled. Lines in the input can end in '\n', '\r', or '\r\n', and
these are translated into '\n' before being returned to the
caller. If it is '', universal newline mode is enabled, but line
endings are returned to the caller untranslated. If it has any of
the other legal values, input lines are only terminated by the given
string, and the line ending is returned to the caller untranslated.
* On output, if newline is None, any '\n' characters written are
translated to the system default line separator, os.linesep. If
newline is '' or '\n', no translation takes place. If newline is any
of the other legal values, any '\n' characters written are translated
to the given string.
If line_buffering is True, a call to flush is implied when a call to
write contains a newline character."""
def close(self, *args, **kwargs): #real signature unknown
關(guān)閉文件pass
def fileno(self, *args, **kwargs): #real signature unknown
文件描述符pass
def flush(self, *args, **kwargs): #real signature unknown
刷新文件內(nèi)部緩沖區(qū)pass
def isatty(self, *args, **kwargs): #real signature unknown
判斷文件是否是同意tty設(shè)備pass
def read(self, *args, **kwargs): #real signature unknown
讀取指定字節(jié)數(shù)據(jù)pass
def readable(self, *args, **kwargs): #real signature unknown
是否可讀pass
def readline(self, *args, **kwargs): #real signature unknown
僅讀取一行數(shù)據(jù)pass
def seek(self, *args, **kwargs): #real signature unknown
指定文件中指針位置pass
def seekable(self, *args, **kwargs): #real signature unknown
指針是否可操作pass
def tell(self, *args, **kwargs): #real signature unknown
獲取指針位置pass
def truncate(self, *args, **kwargs): #real signature unknown
截斷數(shù)據(jù),僅保留指定之前數(shù)據(jù)pass
def writable(self, *args, **kwargs): #real signature unknown
是否可寫pass
def write(self, *args, **kwargs): #real signature unknown
寫內(nèi)容pass
def __getstate__(self, *args, **kwargs): #real signature unknown
pass
def __init__(self, *args, **kwargs): #real signature unknown
pass@staticmethod#known case of __new__
def __new__(*args, **kwargs): #real signature unknown
"""Create and return a new object. See help(type) for accurate signature."""
pass
def __next__(self, *args, **kwargs): #real signature unknown
"""Implement next(self)."""
pass
def __repr__(self, *args, **kwargs): #real signature unknown
"""Return repr(self)."""
passbuffer= property(lambda self: object(), lambda self, v: None, lambda self: None) #default
closed= property(lambda self: object(), lambda self, v: None, lambda self: None) #default
encoding= property(lambda self: object(), lambda self, v: None, lambda self: None) #default
errors= property(lambda self: object(), lambda self, v: None, lambda self: None) #default
line_buffering= property(lambda self: object(), lambda self, v: None, lambda self: None) #default
name= property(lambda self: object(), lambda self, v: None, lambda self: None) #default
newlines= property(lambda self: object(), lambda self, v: None, lambda self: None) #default
_CHUNK_SIZE= property(lambda self: object(), lambda self, v: None, lambda self: None) #default
_finalizing= property(lambda self: object(), lambda self, v: None, lambda self: None) #default
3.x
classfile(object)def close(self): #real signature unknown; restored from __doc__
關(guān)閉文件"""close() -> None or (perhaps) an integer. Close the file.
Sets data attribute .closed to True. A closed file cannot be used for
further I/O operations. close() may be called more than once without
error. Some kinds of file objects (for example, opened by popen())
may return an exit status upon closing."""
def fileno(self): #real signature unknown; restored from __doc__
文件描述符"""fileno() -> integer "file descriptor".
This is needed for lower-level file interfaces, such os.read()."""
return0def flush(self): #real signature unknown; restored from __doc__
刷新文件內(nèi)部緩沖區(qū)"""flush() -> None. Flush the internal I/O buffer."""
pass
def isatty(self): #real signature unknown; restored from __doc__
判斷文件是否是同意tty設(shè)備"""isatty() -> true or false. True if the file is connected to a tty device."""
returnFalsedef next(self): #real signature unknown; restored from __doc__
獲取下一行數(shù)據(jù),不存在,則報錯"""x.next() -> the next value, or raise StopIteration"""
pass
def read(self, size=None): #real signature unknown; restored from __doc__
讀取指定字節(jié)數(shù)據(jù)"""read([size]) -> read at most size bytes, returned as a string.
If the size argument is negative or omitted, read until EOF is reached.
Notice that when in non-blocking mode, less data than what was requested
may be returned, even if no size parameter was given."""
pass
def readinto(self): #real signature unknown; restored from __doc__
讀取到緩沖區(qū),不要用,將被遺棄"""readinto() -> Undocumented. Don't use this; it may go away."""
pass
def readline(self, size=None): #real signature unknown; restored from __doc__
僅讀取一行數(shù)據(jù)"""readline([size]) -> next line from the file, as a string.
Retain newline. A non-negative size argument limits the maximum
number of bytes to return (an incomplete line may be returned then).
Return an empty string at EOF."""
pass
def readlines(self, size=None): #real signature unknown; restored from __doc__
讀取所有數(shù)據(jù),并根據(jù)換行保存值列表"""readlines([size]) -> list of strings, each a line from the file.
Call readline() repeatedly and return a list of the lines so read.
The optional size argument, if given, is an approximate bound on the
total number of bytes in the lines returned."""
return[]def seek(self, offset, whence=None): #real signature unknown; restored from __doc__
指定文件中指針位置"""seek(offset[, whence]) -> None. Move to new file position.
Argument offset is a byte count. Optional argument whence defaults to
(offset from start of file, offset should be >= 0); other values are 1
(move relative to current position, positive or negative), and 2 (move
relative to end of file, usually negative, although many platforms allow
seeking beyond the end of a file). If the file is opened in text mode,
only offsets returned by tell() are legal. Use of other offsets causes
undefined behavior.
Note that not all file objects are seekable."""
pass
def tell(self): #real signature unknown; restored from __doc__
獲取當(dāng)前指針位置"""tell() -> current file position, an integer (may be a long integer)."""
pass
def truncate(self, size=None): #real signature unknown; restored from __doc__
截斷數(shù)據(jù),僅保留指定之前數(shù)據(jù)"""truncate([size]) -> None. Truncate the file to at most size bytes.
Size defaults to the current file position, as returned by tell()."""
pass
def write(self, p_str): #real signature unknown; restored from __doc__
寫內(nèi)容"""write(str) -> None. Write string str to file.
Note that due to buffering, flush() or close() may be needed before
the file on disk reflects the data written."""
pass
def writelines(self, sequence_of_strings): #real signature unknown; restored from __doc__
將一個字符串列表寫入文件"""writelines(sequence_of_strings) -> None. Write the strings to the file.
Note that newlines are not added. The sequence can be any iterable object
producing strings. This is equivalent to calling write() for each string."""
pass
def xreadlines(self): #real signature unknown; restored from __doc__
可用于逐行讀取文件,非全部"""xreadlines() -> returns self.
For backward compatibility. File objects now include the performance
optimizations previously implemented in the xreadlines module."""
pass
2.x
a = open("5.log","r+",encoding="utf-8")
# a.truncate() #依賴于指針,截取數(shù)據(jù),只剩下指針?biāo)谖恢玫那懊娴臄?shù)據(jù)
# a.close() #關(guān)閉
# a.flush() #強(qiáng)行加入內(nèi)存
# a.read() #讀
# a.readline() #只讀取第一行
# a.seek(0) #指針
# a.tell() #當(dāng)前指針位置
# a.write() #寫
c、管理上下文
為了避免打開文件后忘記關(guān)閉,可以通過管理上下文,即:
with open('log','r') as f:
...
如此方式,當(dāng)with代碼塊執(zhí)行完畢時,內(nèi)部會自動關(guān)閉并釋放文件資源。
在Python 2.7 及以后,with又支持同時對多個文件的上下文進(jìn)行管理,即:
with open('log1') as obj1, open('log2') as obj2:
pass
例:
#關(guān)閉文件with
with open("5.log","r") as a:
a.read()
#同事打開兩個文件,把a(bǔ)復(fù)制到b中,讀一行寫一行,直到寫完
with open("5.log","r",encoding="utf-8") as a,open("6.log","w",encoding="utf-8") as b:
for line in a:
b.write(line)
lambda表達(dá)式
學(xué)習(xí)條件運(yùn)算時,對于簡單的 if else 語句,可以使用三元運(yùn)算來表示,即:
# 普通條件語句
if 1 == 1:
name = 'wupeiqi'
else:
name = 'alex'
# 三元運(yùn)算
name = 'wupeiqi' if 1 == 1 else 'alex'
對于簡單的函數(shù),也存在一種簡便的表示方式,即:lambda表達(dá)式
# ###################### 普通函數(shù) ######################
# 定義函數(shù)(普通方式)
def func(arg):
return arg + 1
# 執(zhí)行函數(shù)
result = func(123)
# ###################### lambda ######################
# 定義函數(shù)(lambda表達(dá)式)
my_lambda = lambda arg : arg + 1
# 執(zhí)行函數(shù)
result = my_lambda(123)
遞歸
利用函數(shù)編寫如下數(shù)列:
斐波那契數(shù)列指的是這樣一個數(shù)列 0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233,377,610,987,1597,2584,4181,6765,10946,17711,28657,46368...
def func(arg1,arg2):
if arg1 == 0:
print arg1, arg2
arg3 = arg1 + arg2
print arg3
func(arg2, arg3)
func(0,1)
def func(n,a,b):
if n == 10:
return a
c = a + b
return func(n+1,b,c)
ret = func(1,0,1)
print(ret)
# 列出一組數(shù)據(jù)
a,b = 0,1
while b <1000:
print(a)
a, b = b, a+ b
冒泡排序
# li = [11,2,35,14,22,35235,1232141,345,321423,123,123234]
# for j in range(1,len(li)):
# for i in range(len(li)-j):
# if li[i]
# temp = li[i]
# li[i]=li[i+1]
# li[i+1]=temp
# print(li)
總結(jié)
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