Deep understanding of Python3 built-in functions and deep understanding of python3

Deep understanding of Python3 built-in functions and deep understanding of python3

This article mainly introduces Python3 built-in functions and shares them with you as follows:

Built-in functions

The following code uses Python3.6.1 as an example:

# Coding = UTF-8 # builtin_function.py built-in Function import osdef fun (): all ([True, False]) # all elements of the iterator (empty or) are true, returns true => False any ([True, False]) # returns true => true num = abs (-1.23) if any element of the iterator is True) # absolute value num = pow (5, 3) # Power x ** y => 125 num = pow (5, 3, 3) # x ** y) % z => 2 num = round (1.23) # returns the approximate value of the floating point number. By default, the value is 0, and num = round (1.23, 5) #5 indicates the number of digits after the decimal point to be retained num = sum ([1, 2, 3, 4, 5]) # sums the list numbers and strs = ascii (OS) # returns Ascii string format of the image strs = bin (123) # convert the integer to a binary string (if the converted object is not of the int type, it can be defined in _ index _) boolean = bool (0) # obtain true/False (False: None/False/0/null of any type ""() [] {}/_ bool _ return False/_ len _ return 0) bytes = bytearray ("You were, are and will be in my heart! "," UTF-8 ") # string (string, encoding): Convert to byte sequence/number (number) by encoding: generate an empty array of the corresponding size/No parameter (): 0 array bytes = bytes ("You were, are and will be in my heart! "," UTF-8 ") # Same as bytearray (), but not variable strs = chr (123) # convert the integer (Unicode) to the char type (range: [0, 1 114]) num = ord ("{") # convert char type to INTEGER (Unicode) num = complex ("1 + 2j") # convert string or number to plural (cannot contain spaces) num = float ('1. 1 ') # build floating point strs = format (123, 'F') # format (type: x, B, f... /displacement:> (> 10), <, ^/length: 5/E) strs = hex (123) # convert the integer into a hexadecimal string strs = oct (123) # convert from decimal to an octal string num = int (123.1) # convert it to an integer strs = str (123) # convert the object to a string strs = str (B "123", "utf -8 ") elem = max ([1, 3, 4], [2, 4, 6]) # One iterable or multiple elements can be received => [2, 4, 6] elem = max (,) # => 4 elem = max ([, 6], key = lambda x: x = 2) # => 2 elem = min (1, 2, 3, 4) # contrary to max exe = compile ("print ('O _ o')", filename = 'strs ', mode = 'exec ') # compile as code, mode (compilation mode: executable statement 'exec', single statement 'eval', interactive statement 'single ') exec (exe) # Run the compiled code exec ("print ('O _ o')") # Run the String uncompiled code eval (compile ("print ('O _ o ')", filename = 'Strs', mode = 'eval') # The string type delattr (Clazz ("Hello! ")," Name ") # delete an object attribute = del clazz. name For details, see the reflection code block (http://www.bkjia.com/article/128897.htm) setattr (Clazz (" Hello! ")," Name "," World! ") # Assign strs = getattr (Clazz (" Hello! ")," Name ") # obtain the attribute value strs = getattr (Clazz (" Hello! ")," Name ",-1) #-1 returns boolean = hasattr (Clazz (" Hello! ")," Name ") # whether the object has this attribute lists = dir (Clazz (" Hello! ") # View the function clazz = type (OS) # obtain the type dicts = globals () # obtain the current global function and the object dicts = locals () # obtain the current local function and the object dicts = vars () # Same as locals () (_ dict _) dicts = vars (Clazz ("Hello! ") Num = hash (Clazz (" Hello! ") # Obtain the hash value of an object help (OS) # obtain the help document num = id (OS) of an object) # obtain the id boolean = isinstance (Clazz ("Hello! "), Clazz) # whether the object is an instance of this class boolean = issubclass (Clazz, Clazz) # Whether the class (Before) is a subclass of this class (after) (including itself) strs = repr (OS) # convert the object into a string expression #-super () # proxy parent class object, see the class article (http://www.bkjia.com/article/88315.htm) #-memoryview (obj) for details) # Memory view, detailed description of the data structure article (http://www.bkjia.com/article/128892.htm) dics = dict () # create a dictionary tups = divmod (10, 5) # Return tuples, (vendor (10/5 ), remainder (10% 5) lists = enumerate (['A', 'B', 'C']) # returns the enumerated object lists = filter (lambda x: true if (ord (x)> 66) else False, ['A', 'B', 'C']) # function is reserved for Frue, false remove sets = frozenset ([1, 2, 3]) # Return the new frozenset object (SET) num = len ([1, 2, 3]) # length lists = list (1, 'A') # convert to list type tups = tuple ([1, 2, 3]) # convert to tuple tuples type ran = range (5) # immutable sequence ran = range () ran = range (, 2) # (START, end, increase) sets = set ([1, 2, 3]) # returns the set maps = map (lambda x, y: x * y, [1, 2, 3], [65, 66, 67, 68]) # returns an iterator. elements are filtered by custom functions and multiple iterable parameters can be received: [65,132,201] iters = zip (["", "B", "C", "D", "E", "F"], [1, 2, 3]) # create a new iterator, aggregate each iterator element => [('A', 1), ('B', 2), ('C', 3)] iters = iter ([1, 2, 3, 4, 5]) # Return an iterator object elem = next (iters) # obtain the next element from the iterator; for the implementation principle, see the built-in function Article lis block code (http://www.bkjia.com/article/128890.htm) iters = reversed ([, 3]) # returns the reverse traversal Server => [3, 2, 1] lists = [1, 2, 4, 5] [slice (3)] # slice => [1, 2, 3] lists = [1, 2, 3, 4, 5] [slice (1, 3)] # [slice (3) = slice (None, 3, None)/slice (1, 3) = slice (1, 3, None) /slice (, 1) = slice (1, 3, 1) lists = sorted ([, 4]) # Sort => [1, 2, 3, 4, 5] lists = sorted (['A', 'B', ';', 't', 'D', '1'], key = lambda x: ord (x), reverse = True) # key: Comparison key function. Does reverse traverse strs = input ("Please input data :") # input data f = open ("temp.txt", "r +") # open the file. For details, see the operating system Article print ("string % d" % 123) # print character => string 123 print ("Word", "character", "string", sep = "-") # sep is separator => character-string print ("Word", "character", "string", sep = "-", end = "\ r \ n ") # end: end => character-string/r/n print ("Word", "character", "string", sep = "-", end = "\ r \ n", file = open ("temp.txt", "w +") # print to the file class Clazz: def _ init _ (self, name): self. name = name; @ classmethod # wrap the function into the class method def setName_cls (cls, name): pass @ staticmethod # package the function into the static method def setName_sta (name ): pass def getname (self): return self. name def setname (self, value): self. name = value def delname (self): del self. name # property (fget = None, fset = None, fdel = None, doc = None) # returns a property attribute # property is an attribute method, which can be implemented in two ways, for details, see the attribute method code block of the class article (http://www.bkjia.com/article/68235.htm) x = property (getname, setname, delname) if _ name _ = "_ main _": fun () # use c = Clazz ("Liu Yan") print (c. x) # => Liu Yan c. x = 'tang wei' print (c. getname () # => Tang Wei del c. x

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