1. The default parameters of the function must be immutableIf the default parameter of a function is a mutable object, then the default parameter is modified outside the function and affects the function itself.def spam (A, b=None): # B to be an immutable parameter, you cannot use a variable parameter such as an empty list [] ... if is None: ... = []...2. Anonymous functions1. You can use anonymous functions when you can't think of a function name or want a short operationLambda
Cat/etc/issueCat/etc/redhat-release rpm-qa| grep releaseView versionUname-a-i-r View kernel versionYum Grouplistlang=enYum grouplist This command to list all installed and not installed packagesReboot;init 6 Shutdown-r now offSingle-run mode change passwordpasswd Change PasswordRestart linux,3 seconds, press ENTER. If you have a grub password, you need to press P first, enter the password before you can do the followingPress E, select the second row, and then press eadd single or number 1 or let
string-S: Replace duplicate characters!Example: [Root @test/root]# Last | TR ' [A-z] ' [A-z] ' [Root @test/root]# cat/etc/passwd | Tr-d: [Root @test/root]# Cat/home/test/dostxt | Tr-d ' \ r ' > Dostxt-nomSplitSyntax: [Root @test/root]# split [-BL] input file output file leading characterParameter description:-B: Divide by file size-L: divided by the number of rowsExample: [Root @test/root]# split-l 5/etc/passwd test Description: It's a lot easier under Linux! If you want to split the file, then
14.10 re-throw the caught exception?You caught an except exception in a block and now want to re-throw it.Solution?Simply use a single rasie statement, for example:>>>DefExample():...Try:...int ( ' n/a ' ) ... except valueerror: ... print ( "didn ' t work" ) ... raise ... >>> example () didn ' t work traceback (most recent call last): File "1, in span class= "n" > "3, in Examplevalueerror: invalid literal for int. () with base: ' N/a ' > >> Discuss?The problem is usually when y
), which provides CLI programs with a virtual machine environment that uploads and runs managed code on a variety of possible platforms, is just a specification, for example, Microsoft and Momo have their own implementations. The JIT and GC of the CLR for net should fall into this scope.The. NET Framework is a Microsoft implementation of the CLI, and, of course, the best implementation of the present, the. NET Framework mainly includes the CLR and the BCL,CLR is the core of the implementation of
operation time complexity is O (log N), where n is the size of the heap, so even when N is very large, they are still running fast. In the above code, the queue contains a tuple (-priority, index, item). The goal of a negative priority is to make the element sort from highest to lowest priority. This sort of heap is the opposite of regular sort by priority from low to high. The role of the index variable is to ensure that the same priority elements are sorted correctly. By saving an ever-increa
a Python object to the corresponding C parameter.This section of code uses Python's caching protocol to match any input parameter that looks like a double-precision array(such as numpy arrays, arrays created by array modules, etc.), refer to section 15.3 for more information.Inside the TYPEMAP code, variable substitution such as $ and $ will get the C parameter value of Typemap mode(for example, map to double*a ). $input point to a parameter as input PyObject* ,And $argnum it represents the num
;Fromllvm.eeImportExecutionengine>>>Engine=Executionengine.New(MoD)>>>Ptr=Engine.Get_pointer_to_function(F)>>>Ptr4325863440>>>Foo=cTYPES.Cfunctype(cTYPES.C_double,cTYPES.c_doublectypes. C_double) (ptr) >>> # Call the resulting Function>>> foo (23) 13.0>>> foo (4,5) Span class= "Go" >41.0>>> foo (1 ,2) 5.0>>> It's not that making any mistakes at this level will cause the Python interpreter to hang up.Remember that you are dealing directly with machine-level memory addresses and local machine c
1. Traversing a stringThere is no iterative operation in SQL, so you can implement this process by connecting a table that is used as a traversal pointer.1 Selectsubstr (E.ename, Iter.pos,1) asC2 from(SelectEname fromEmpwhereEname= 'KING') E,3(SelectId asPos fromT10) ITER4 whereIter.posLength (e.ename);There are 10 data in T10, ID from 1-10.The FROM clause provides a Cartesian product, and the resulting table resemblesThe WHERE clause restricts the POS range. SQL
# Define debug_variable "snort_debug"The system environment variable contains a variable named snort_debug.Next is the macro definition of debug_lever of each module.
1
# Define
Debug_all 0 xffffffff
2
# Define
Debug_init 0x00000001
Http://www.cppblog.com/mzty/archive/2007/03/04/19163.html C ++ random Classification List (advanced)
C ++ casual Classification List (advanced ):
C ++ highlights:61 object-oriented design principles Http://www.cppblog.com/mzty/archive/2005/12/29/22
Simulate generic
Java's generic system cannot work well with its dynamic reflection API. for jmock, this means that when you simulate generics, the compiler will warn you of possible static type errors. the warning is incorrect. the best way to
Briefly introduces the basic classes of OC.
CategoryOC's built-in capability to expand already-existing classes is one of its most powerful features. This behavioral expansion is called a category. Categories extend class functionality without
This book is not intended for beginners. This book mainly explains how to use some ready-made class libraries, including the C ++ standard library and boost library.
Chapter 4 Create a c ++ Application
1. Compile, Link, static/dynamic library
2.
IntroductionSQL is a language in the computer world. When developing reports using relational databases, you need SQL knowledge to put data into databases and obtain data from databases. Many people use SQL in a careless manner and do not realize
Given a dictionary D, direct d [Key] = value. If the key is not D, an entry is automatically added to D.
D = {'name': 'Small C '}Print dD ['age'] = 21Print d
---------- Python ----------{'Name': '\ xd0 \ xa1c '}{'Age': 21, 'name': '\ xd0 \ xa1c '}
The model class for deleting data CakePHP provides several methods to delete records from the database. Deletedelete (int $ id = null, boolean $ cascade = true); delete a record with $ id. By default, records that depend on deleted records are also
Although there are a lot of questions, they are the most common ones. If you are ready to participate in the relevant interview, it is best to see. In particular, the last dozens of multinational companies face questions. Now many domestic
1, String propertyView the systems that have those character sets:If you need to store from multiple languages into the same column, you will consider the Unicode character set (UTF8 or UCS2), only it can represent multiple language charactersSome
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