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1. File related function # refresh buffer "" # refresh buffer flush # automatically flush the buffer when the file is closed # automatically flush the buffer when the whole program is finished # automatically flush the buffer when the buffer is full # manually refresh the buffer "fp = open (" ceshi1.txt ", mode=" a ") Encoding= "utf-8") fp.write ("abc") # manually flush the buffer and write the contents directly to the file fp.flush () while True: passfp.close () "" # File related functions "fp" the object itself is an iterator, and the contents of the file can be traversed line by line "fp = open (" ceshi1.txt ", mode=" r "). Encoding= "utf-8") # readable () function: judge whether a file object is readable print (fp.readable ()) # writable () function: determine whether a file object is writable print (fp.writable ()) # traversal fp file object for i in fp: print (I) "" # 1.readline () function: read a line of file contents''with open ("ceshi1.txt", mode= "r") Encoding= "utf-8") as fp: res = fp.readline () print (res) # (1) read it all at once with open ("ceshi1.txt", mode= "r") Encoding= "utf-8") as fp: # first read a line res = fp.readline () # to determine whether it is empty, not empty in the loop while res: print (res) # read a line and put it in the loop. Res = fp.readline () # (2) Note: readline (number of characters read) print ("") with open ("ceshi1.txt", mode= "r", encoding= "utf-8") as fp: number of characters read > actual number of characters on the current line = > number of characters read according to the current line

< 实际当前行字符数量的时候 =>

Read "" res = fp.readline (300) print (res)''print ("") # 2.readlines () function: read the contents of the file into the list according to the newline lst_new = [] with open ("ceshi1.txt", mode= "r +") Encoding= "utf-8") as fp: lst = fp.readlines () for i in lst: lst_new.append (i.strip ()) print (lst_new) # 3.writelines () function: write repeatability data of string content to file parameters: iterative data of string type lst = ['bright moonlight in front of bed', 'like cold frost on the ground' With open ("ceshi2.txt", mode= "w+", encoding= "utf-8") as fp: fp.writelines (lst) # achieve effect: add a line break effect, and insert a sentence: Wang Wen is really handsome, insert the content in front of bowing his head and thinking about home lst_new = [] # insert the content into the original list lst.insert (- 1) ("Wang Wen is really handsome") # Loop the original list, put each element together\ ninto the new list for i in lst: lst_new.append (I + "\ n") print (lst_new) # insert each line in the new list into the file with open ("ceshi2.txt", mode= "w +", encoding= "utf-8") as fp: fp.writelines (lst_new) # Note, the content must be a string Cannot be integer "lst = [1Jing 2jue 3] with open (" ceshi2.txt ", mode=" w+ ", encoding=" utf-8 ") as fp: fp.writelines (lst)"# 4.truncate () function: extract the string to be intercepted, then empty the content and rewrite the extracted string into the file (bytes) with open (" ceshi2.txt ", mode=" r + ") Encoding= "utf-8") as fp: fp.truncate (3) "" seek (byte) truncate (byte) read (character / byte) readline (character / byte) "" 2. Function _ function parameter 2.1 function # function "concept: function (wrapping a part of the code to achieve a certain function to achieve a certain purpose) characteristics: it can be called repeatedly to improve the reusability of the code and improve the development efficiency. Easy maintenance and management. Function basic format "" # define a function def function name (): code1 code # call function name () "" # define function def func (): print ("I am a function.") # call function func () # 2. The function is named "" alphanumeric underscore, the first character cannot be strictly case-sensitive, and it is meaningful to use keyword functions. And cannot use Chinese, oh hump nomenclature: (1) Big hump nomenclature: the first character of each word should be capitalized (class naming) mycar = > MyCar (2) small hump nomenclature: except for the first word in lowercase. The first characters of the remaining words are capitalized (function or variable) mycar = > myCar_ nomenclature: different words can be concatenated with _ mycar = > my_car symmetric_differencesymmetricDifference SymmetricDifference "" # function definition def cfb_99 (): for i in range (1d10): for j in range (1) Item1): print ("{: d} * {: d} = {: 2d}" .format End= "") print () # call function for i in range (5): parameter of cfb_99 () 2.2.The parameter of function # Parameter of function "" parameter: type of value parameter needed for function operation: (1) formal parameter: formal parameter, at the definition of function (2) argument: actual parameter The types of formal parameters in the call of the function: 1. Common formal parameter (position formal parameter) 2. Default parameter 3 general collection parameter 4. Name key shape Ref. 5. Keyword collects the types of formal parameters: 1. Common actual reference 2. Keyword argument principle: one-to-one correspondence between formal parameter and actual parameter "# 1. General formal parameter (position parameter) # define function" hang,lie common formal parameter, at the function definition "def small_star (hang,lie): I = 0 while I

< hang: j = 0 while j < lie: print("*",end="") j +=1 print() i += 1# 调用函数"""10,10普通实参,在函数的调用处"""small_star(10,10)small_star(2,3)# 2.默认形参 """hang,lie默认形参,在函数定义处""""""如果给予实参,那么使用实参如果没有给予实参,那么使用参数身上的默认值"""def small_star(hang=10,lie=10): i = 0 while i < hang: j = 0 while j < lie: print("*",end="") j +=1 print() i += 1small_star(4,8)small_star(8)small_star()# 3.普通形参 + 默认形参"""普通形参必须写在默认形参的前面不能调换位置"""def small_star(hang,lie=10): i = 0 while i < hang: j = 0 while j < lie: print("*",end="") j +=1 print() i += 1small_star(5,7)# small_star(5)# small_star() error# 4.关键字实参print("")"""1.如果都是关键字实参,可以任意调整实参的顺序2.普通实参必须写在关键字实参的前面"""def small_star(hang,a,b,c,lie=10): i = 0 while i < hang: j = 0 while j < lie: print("*",end="") j +=1 print() i += 1# hang a ... lie 具体指定参数的值叫做关键字实参,在函数的调用处;# small_star(hang=3,a=4,b=5,c=6,lie=7)# small_star(b=5,c=6,lie=7,a=4,hang=3)small_star(3,4,b=5,c=6,lie=7)small_star(3,4,b=5,lie=7,c=6)# small_star(b=5,c=6,lie=7,3,4) error3. 收集参数# ### 收集参数"""(1) 普通收集形参: 专门用来收集那些多余的没人要的普通实参 收集之后,会把多余实参打包成一个元组 参数头上1个星星 def func(*args): pass args =>

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