# iterator fromcollectionsimportiterablefromcollectionsimportiterator# The data types that can directly act on for a loop have the following #1. Collection data types, such as list, tuple, dict, set, SRT, and #2.generator, including generators and yield generator function# these objects, which can be directly applied to a for loop, are called iterative objects:iterable# use Isinstance () to determine whether an object is a Iterable object print ( Isi
.__next_ _ () print (' Start ready to make buns! ') For I in range: time.sleep (1) print ("Made 2 buns!") C.send (i) c2.send (i) Producer ("Mike") Three, iteratorsWe already know that for there are several types of data that can be directly acting on a loop:A class is a collection of data types:,,,, list tuple dict set str ;The class is: generator , including the generator and yield the generator function with the band.These objects, which can be directly appli
Python provides a number of built-in functions.First, the numerical processing correlation function:1, take absolute value: ABS ()def # Real signature Unknown """ "" " passABS ()2. Turn binary: Bin ()def # "" " Return The binary representation of an integer. >>> bin (2796202) ' 0b1010101010101010101010 ' "" "3, turn octal: Oct ()def # "" " Return The octal representation of an integer. >>> Oct (342391) ' 0o1234567 ' "" "4, ext. 16: Hex
a List of 1000 elements, and the code:For I in Xrange (£): PassThe next value is returned in each iteration, and the memory footprint is small. Because Xrange does not return a List, it returns a generator, (List is an iterative object). An iterative object can return a iterator object by calling the Iter method, and then for loop access:class Iterable_: def __iter__ (self): return iter ([1, 2, 3]) = iter ((Iterable_ ())) it: Print "
Map (function, iterable, ...)Apply function to every item of iterable and return a list of the results. If additional iterable arguments is passed, function must take that many arguments and is applied to the items from all I Terables in parallel. If one iterable is shorter than another it's assumed to be extended with
Built-in functions-scopes-closures-recursion1. Several built-in functions that may be usedView built-in functions: Print (DIR (__builtins__)) Common functions: Len for length min min Max maximum sorted sort, small to large reversed inverse sum summation conversion: The bin () conversion to the binary Oct () conversion to octal hex () to Hex ord () converts the character to the corresponding ASIIC code value CHR () converts the ASIIC code value to the corresponding character supplement: 1.enum Er
In the process of using Python, it is easy to confuse the following concepts of correlation:
Container (Container)
An iterative object (iterable)
Iterators (Iterator)
Generator (Generator)
Builder expression
{list, set, dict} analytic type
1. Container (Container)A container is a data structure used to store elements, which supports the test of membership, where the container stores all the data in memory, and typical
Official explanation:
Apply function of two arguments cumulatively to the ' items of iterable, from left to right, so as to reduce the iterable to A single value. For example, reduce (lambda x, Y:x+y, [1, 2, 3, 4, 5]) calculates ((((1+2) +3) +4). The left argument, X, are the accumulated value and the right argument, y, are the update value from the iterable
// Tabs = 2// Configure //-----------------------------------------------------------------------------------------------//// MD5 message-digest for Delphi 4//// Delphi 4 unit implementing// RSA Data Security, Inc. MD5 message-Digest algorithm//// Implementation of Ronald L. Rivest's RFC 1321.//// Copyright? 1997-1999 medienagentur fichtner Meyer// Written by Matthias fichtner//// Configure //----------------------------------------------------------
Now we prepare information for second H. 264 codecs comparison test, that will be compared with more advanced metrics. so we collect information about current available codecs and there stage. if you have any information about this codecs or another codecs please replay this message!List of MPEG-4 AVC/H.264 video codecs(Last updated 1 December 2005-62 items now !)
----------------------------------------------------------
Software codecs:
---------------------
Ateme H.264/MP
, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00,$00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00,$00, $00, $00, $00, $00, $00, $00, $00 );
Implementation
Function F (x, y, z: DWORD): DWORD;BeginResult: = (x and y) or (not x) and z );End;
Function G (x, y, z: DWORD): DWORD;BeginResult: = (x and z) or (y and (not z ));End;
Function H (x, y, z: DWORD): DWORD;BeginResult: = x xor y xor z;End;
Function I (x, y, z: DWORD): DWORD;BeginResult: = y xor (x or (not z )
driver of PostgreSQL, Informix, and Sybase is contributed by the development of the free software community ).
One of the biggest advantages of using ADODB is that, regardless of the backend database, the methods for accessing the database are the same, so developers do not have, however, you must learn another set of different access methods, which greatly reduces the knowledge burden on developers. the previous knowledge can still be used in the future. when the database platform is transfer
is invalid, and then threads 1 read, found that their cache row is invalid, It waits for the cache line corresponding to the main memory address to be updated, and then goes to the corresponding main memory to read the latest value.
Then thread 1 reads the latest correct value.
2.volatile guaranteed atomicity.
Knowing the volatile keyword above guarantees the visibility of the operation, but volatile guarantees that the operation of the variable is atomic.
Let's look at an example:
public
layer, is the CPU L1 or L2 cache of the corresponding cache line invalid);
Third: Because the cached row of the cached variable stop in thread 1 's working memory is invalid, thread 1 reads the main memory again when the value of the variable stop is read.
Then thread 2 modifies the stop value (there are 2 operations here, of course). Modifying the value in the thread 2 working memory and then writing the modified value to memory invalidates the cached row of the cached variable stop in the w
before writing the volatile variable).Thread A writes a volatile variable, and then thread B reads the volatile variable, which essentially is thread a sending a message to thread B through main memory.
Does 5.volatile guarantee atomic sex?
Knowing from above that the volatile keyword guarantees the visibility of the operation, but does volatile guarantee that the operation of the variable is atomic?
Let's look at an example:
public class Test {public
volatile int
that can directly act on a for loop are called an iterative object: Iterable.You can use Isinstance () to determine whether an object is a Iterable object:xuliangwei:~ xuliangwei$ Python3>>>>>> from collections Import iterable>>> isinstance ([], iterable)True>>> isinstance ({}, iterable)True>>> isinstance (' abc ',
I. Basic data typesInteger: intString: str (note: \ t equals a TAB key)Boolean value: BOOL Listing: Listlist with []Ganso: TupleFor Ganso ()Dictionary: DictNote: All data types exist in the class column that you want to correspond to.Two. List all data types:Basic operation:
Index
Slice
Additional
Delete
Length
Slice
Cycle
Contains
ListclassList (object):"""list (), New empty list List (iterable), new list in
Guide to Using reduce built-in functions in python, pythonreduce
Official explanation:
Apply function of two arguments cumulatively to the items of iterable, from left to right, so as to reduce the iterable to a single value. For example, reduce(lambda x, y: x+y, [1, 2, 3, 4, 5]) calculates ((((1+2)+3)+4)+5). The left argument, x, is the accumulated value and the right argument, y, is the update value from
Python built-in functions
Dir (_ builtins __)
1. 'abs '. Obtain the absolute value of the input parameter.
abs(x, /) Return the absolute value of the argument.
1 >>> abs(10)2 103 >>> abs(-10)4 10
2. 'all' is used to determine whether all elements in the given iterable parameter are not 0, '', False, or iterable empty. If yes, True is returned. Otherwise, False is returned.
all(
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