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1. Top results related to what are the function of dictionary in c compiler design in python

   • What are the attributes of 'urlretrieve' function in Python?

     Top Answer

     Answered Nov 04, 2015 · 0 votes

     If we take a look at the official Python documentation for urllib.urlretrieve

     , we get a nice explanation:

     Copy a network object denoted by a URL to a local file, if necessary. If the URL points to a local file, or a valid cached copy of the object exists, the object is not copied. Return a tuple (filename, headers) where filename is the local file name under which the object can be found, and headers is whatever the info() method of the object returned by urlopen() returned (for a remote object, possibly cached). Exceptions are the same as for urlopen().

     The second argument, if present, specifies the file location to copy to (if absent, the location will be a tempfile with a generated name). The third argument, if present, is a hook function that will be called once on establishment of the network connection and once after each block read thereafter. The hook will be passed three arguments; a count of blocks transferred so far, a block size in bytes, and the total size of the file. The third argument may be -1 on older FTP servers which do not return a file size in response to a retrieval request.

     If the url uses the http: scheme identifier, the optional data argument may be given to specify a POST request (normally the request type is GET). The data argument must in standard application/x-www-form-urlencoded format; see the urlencode() function below.

     Changed in version 2.5: urlretrieve() will raise ContentTooShortError

     when it detects that the amount of data available was less than the expected amount (which is the size reported by a Content-Length header). This can occur, for example, when the download is interrupted.

     The Content-Length is treated as a lower bound: if there’s more data to read, urlretrieve() reads more data, but if less data is available, it raises the exception.

     You can still retrieve the downloaded data in this case, it is stored in the content attribute of the exception instance.

     If no Content-Length header was supplied, urlretrieve() can not check the size of the data it has downloaded, and just returns it. In this case you just have to assume that the download was successful.

     By the way, they're called arguments or parameters, not attributes.

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     1/5

   • What are is the use of 'top' function in describe(include='all') in python?

     Top Answer

     Answered Feb 26, 2019 · 3 votes

     what is the purpose of top function in output, and how it will work?

     If you execute:

     df.Name.value_counts()-

     You will see the value of a person in the Name column and their counts. top gives the highest counted value of the categorical values.

     Example:

     d ={'Name':pd.Series(['Tom','Steve','Ricky','Vin','Steve','Smith','Jack','Lee','David','Gasper','Betina','Andres']),'Age':pd.Series([25,26,25,23,30,29,23,34,40,30,51,46]), 'Rating':pd.Series([4.23,3.24,3.98,2.56,3.20,4.6,3.8,3.78,2.98,4.80,4.10, 3.65])}#Create a DataFramedf = pd.DataFrame(d)print(df.describe(include='all'))- Name Age Ratingcount 12 12.000000 12.000000unique 11 NaN NaNtop Steve NaN NaNfreq 2 NaN NaNmean NaN 31.833333 3.743333std NaN 9.232682 0.661628min NaN 23.000000 2.56000025% NaN 25.000000 3.23000050% NaN 29.500000 3.79000075% NaN 35.500000 4.132500max NaN 51.000000 4.800000-print(df.Name.value_counts())-Steve 2Ricky 1Tom 1Andres 1Jack 1Smith 1Lee 1Betina 1Vin 1Gasper 1David 1-

     Since Name count for Steve is highest, it comes in top.

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     2/5

   • What is the equivalent of the C _IOR function in Python?

     Top Answer

     Answered Nov 09, 2016 · 1 votes

     'keys' is an integer character constant (containing four characters), the value of which is implementation-defined. You stated that the value returned by the C code _IOR('keys', 1, unsigned char *) is -444763391, which is, as a 4 byte hex number, 0xE57D7301. From that we can conclude that this implementation computes the integer value 0x6B657973 of 'keys' from 'k'<<24|'e'<<16|'y'<<8|'s'. The _IOR value 0xE57D7301 results from the expression

     2<<30|4<<16|'keys'<<8|1: : : :: : : 1 = num n: : 'keys' = group g: 4 = sizeof (unsigned char *)2 = _IOC_READ-

     - note that only 8 Bits are reserved for a TYPE (group) value, and this creative use of a 32 bit value makes the TYPE overflow into the SIZE and DIR bits (getting ORed with them) and its most significant byte (resulting from 'k'<<24) even gets shifted out of the int value.

     With your Python function you can compute the same value by calling

     _IOR(ord('e')<<16|ord('y')<<8|ord('s'), 1, 4)-

     (since the k gets lost, we can drop it outright).

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     3/5

   • What's the equivalent of Python function decorators in C++?

     Top Answer

     Answered Jun 26, 2023 · 11 votes

     Although C++ does not have explicit language support for decorators, it turns out that you can "emulate" them quite nicely using C++14 generic lambdas. Here is my take on it:

     #include <iostream>-template<class T>auto decorator(T&& func){ // we create a closure below auto new_function = [func = std::forward<T>(func)](auto&&... args) { std::cout << "BEGIN decorating...\n"; auto result = func(std::forward<decltype(args)>(args)...); std::cout << "END decorating\n"; return result; }; return new_function;}int f(int x){ std::cout << x * x << '\n'; return x * x;}auto decorated = decorator(f);auto double_decorated = decorator(decorator(f));int main(){ decorated(5); double_decorated(10);}

     Live on Coliru

     Of course inside the decorator you can add whatever you want (including timing etc.), above is just a minimal example. If it looks too daunting you can ignore std::forward and C++14 generalized lambda captures and simply have

     #include <iostream>-template<class T>auto decorator(T func){ // we create a closure below auto new_function = [func](auto... args) { std::cout << "BEGIN decorating...\n"; auto result = func(args...); std::cout << "END decorating\n"; return result; }; return new_function;}int f(int x){ std::cout << x * x << '\n'; return x * x;}auto decorated = decorator(f);auto double_decorated = decorator(decorator(f));int main(){ decorated(5); double_decorated(10);}

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     4/5

   • In Python, if I type a=1 b=2 c=a c=b, what is the value of c? What does c point to?

     Top Answer

     Answered Oct 07, 2018 · 0 votes

     Well, in your code:

     a=1b=2c=ac=b-

     Before you assign c to b's value and after you assign c to a's value, c will be a.

     And after, at the end of the code, c will be b, because you're reassigning the variable.

     The second assignment, basically creates new variable, without knowing that the variable is there already, so it will just do it but no way of accessing previous holding-value of the varaible

     Other Answers

     Answered Oct 07, 2018 · 15 votes

     There are no pointers to variables in Python. In particular, when you say this:

     Is the statement replacing the pointer c -> a with pointer c -> b...

     Python does not have any such thing as "the pointer c -> a", so it is not doing that.

     ...or grabbing the value from b and overwriting a with b's value

     but there is no assignment to a, so it's not doing that either.

     Instead, Python keeps a symbol table1 that maps each name (a, b, c, etc.) to a pointer to an object. In your code sample, after you assign to a and b, it would look like this (obviously I have made up the memory addresses):

     a -> 0xfffa9600 -> 1b -> 0xfffa9608 -> 2-

     and then after you assign c = a, it would look like this:

     a -> 0xfffa9600 -> 1b -> 0xfffa9608 -> 2c -> 0xfffa9600 -> 1-

     Note that c is entirely independent of a. When you run c = b, it replaces the pointer associated with c in the symbol table with the pointer that was associated with b, but a is not affected:

     a -> 0xfffa9600 -> 1b -> 0xfffa9608 -> 2c -> 0xfffa9608 -> 2-

     In this case that's pretty much all there is to it because the objects in question, namely the integer constants 1 and 2, are immutable. However, if you use mutable objects, they do start to act a bit more like pointers in the sense that changes to the object when it's stored in one variable are reflected in other variables that refer to the same object. For example, consider this sample of code:

     x = {'a': 1, 'b': 2}y = x-

     Here, the symbol table might look something like this:

     x -> 0xffdc1040 -> {'a': 1, 'b': 2}y -> 0xffdc1040 -> {'a': 1, 'b': 2}-

     If you now run

     y['b'] = y['a']-

     then it doesn't actually change the pointer associated with y in the symbol table, but it does change the object pointed to by that pointer, so you wind up with

     x -> 0xffdc1040 -> {'a': 1, 'b': 1}y -> 0xffdc1040 -> {'a': 1, 'b': 1}-

     and you'll see that your assignment to y['b'] has affected x as well. Contrast this with

     y = {'a': 1, 'b': 2}-

     which actually makes y point at an entirely different object, and is more akin to what you were doing before with a, b, and c.

     1Actually there are several symbol tables, corresponding to different scopes, and Python has an order in which it checks them, but that detail isn't particularly relevant here.

     Other Answers

     Answered Oct 07, 2018 · 7 votes

     c doesn't "Point at a

     or b

     "... it points at the 1 or 2 objects.

     >>> a = 1>>> b = 2>>> c = a>>> c1>>> c = b>>> c2>>> b = 3>>> c2

     This can be proven somewhat with id() - b and c point at the same "thing":

     >>> b = 2>>> c = b>>> id(b)42766656>>> id(c)42766656

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2. stackoverflow.com › questions › 3269881How to represent a Python-like dictionary in C - Stack Overflow

   stackoverflow.com › questions › 3269881

   • Cached

   In Python it's easy: x = {} x['USD'] = "Dollars" x['CLP'] = "Pesos" or . y = {'lat': 23.678900, 'lng': 121.451928, 'name': "Sin City"} I think most of these kinds of problems have been solved, so where can I get information about dictionaries in C? I do not want to reinvent the wheel. How do I implement a dictionary in C?

3. www.geeksforgeeks.org › compiler-design-ll1-parserCompiler Design LL(1) Parser in Python - GeeksforGeeks

   www.geeksforgeeks.org › compiler-design-ll1-parser

   • Cached

   • LL(1) Grammar
   • Concept of First and Follow
   • Parsing Table
   • Approach
   • Approach For String Validation
   • Inference

   The first ‘L’ in LL(1) stands for scanning the input from left to right, the second ‘L’ stands for producing a leftmost derivation, and the ‘1’ for using one input symbol of lookahead at each step to make parsing action decisions. LL(1) grammar follows Top-down parsing method. For a class of grammars called LL(1) we can construct grammars predictiv...

   See full list on geeksforgeeks.org

   The construction of a top-down parser is aided by FIRST and FOLLOW functions, that are associated with a grammar G. During top-down parsing, FIRST and FOLLOW allow us to choose which production to apply, based on the next input symbol. Rules for First computation: Rules for Follow computation: Note:Epsilon (ε) can never be present in FOLLOW of any ...

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   After the construction of the parsing table, if for any non-terminal symbol in the table we have more than one production rule for any terminal symbol in the table column the grammar is not LL(1). Otherwise, then grammar is considered as LL(1). Rules for construction of parsing table: The assumptionmade in code:

   See full list on geeksforgeeks.org

   There are seven functions and the driver code, they together execute the calculations. Code takes grammar rules as input. The user is required to determine which symbols are terminals (list: term_u...

   Code is executed on the sample set 5 for demo purpose as shown in code, this grammar has left recursion, function computeAllFirsts() is called. This function is responsible for calling functions re...

   Base condition of first() is whether an epsilon or terminal symbol is present, for every non-terminal code enters a recursive logic and if the FIRST has multiple symbols, a list is returned else a...

   FIRST computation is the prerequisite for FOLLOW computation as follow() function has multiple calls to first() function. A start_symbol is the LHS symbol of First rule given in the ‘rules’ list. (...

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   After the parsing table is generated, we must validate the input string for the given grammar. We make use of the stack and buffer for this purpose. If grammar is not LL(1) String validation cannot...

   Then we iteratively traverse over the current state of stack and buffer and match the entries of Table[x][y], where ‘x’ is a symbol at top of the stack and ‘y’ is a symbol at the rear of the buffer...

   If x and y both symbols are the same terminals, then we pop them from both stack and buffer and continue computation. If the stack and buffer remain with only ‘$’ symbol, this shows that all input...

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   Sample set 7 is used to represent code output, it covers all the aspects of LL(1) parsing. Grammar after left recursion removal and after left factoring is printed. After that, we also have first and follow computation results. Then we generate the parsing table, if there are no multiple entries at any position (Table[NT][T]) in the table, we say g...

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4. People also ask

   What's the difference between Python Dict and C++ Dict?

   • @juanchopanza Yup, you're right. When you noted that i noticed the first element of each pair is actually unique and corresponds to what looks like an index into a 1D array. The C++ equivalent of Python's dict is std::map.

   C++ equivalent of Python dictionaries - Stack Overflow

   stackoverflow.com/questions/27674009/c-equivalent-of-python-dictionaries

   See all results for this question

   What is compiler code?

   • Compiler code is not something that is immediately obvious just from the variable names you’re using. This is mainly for yourself! It is highly recommended to divide your code into modules such as the ones introduced in this tutorial, it let’s you worry about less things at a time and keeps you organized. Write unit tests.

   How to write C compiler from scratch with Python! | Medium

   medium.com/@pasi_pyrro/how-to-write-your-own-c-compiler-from-scratch-with-python-90ab84ffe071

   See all results for this question

   Is a C compiler a full implementation of the C language?

   • As will become apparent shortly it is not a full implementation of the C language nor is it a full standalone compiler (actually only the Front-End of a compiler, to be precise) either. Furthermore, it lacks a code optimizer module, which is actually the biggest part of modern compilers.

   How to write C compiler from scratch with Python! | Medium

   medium.com/@pasi_pyrro/how-to-write-your-own-c-compiler-from-scratch-with-python-90ab84ffe071

   See all results for this question

   Should I write a compiler in C?

   • No really, it will drive you mad if you write something like a compiler in C. You will come to appreciate Python’s flexibility like you’ve never had before. Although if you’re writing production code (which you probably shouldn’t, just use GCC or Clang for goodness’ sake!), it might be another story if compilation times matter.

   How to write C compiler from scratch with Python! | Medium

   medium.com/@pasi_pyrro/how-to-write-your-own-c-compiler-from-scratch-with-python-90ab84ffe071

   See all results for this question

5. medium.com › @pasi_pyrro › how-to-write-your-own-cHow to write C compiler from scratch with Python! | Medium

   medium.com › @pasi_pyrro › how-to-write-your-own-c

   • Cached

   Sep 28, 2020 · If you want to experiment with the real compiler implementation while following this tutorial, follow the setup instructions in github and run the following command. python compiler.py input/input ...

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6. stackoverflow.com › questions › 27674009C++ equivalent of Python dictionaries - Stack Overflow

   stackoverflow.com › questions › 27674009

   • Cached

   Dec 28, 2014 · The C++ equivalent of Python's dict is std::map. To initialize a map using a similar syntax, do this: std::map<int,int> myMap = {{4,3}, # center = 3. {0,2},{2,2},{6,2},{8,2}, # corners = 2. {1,1},{3,1},{5,1},{7,1}}; # sides = 1. Note that this needs C++11.

   Code sample

   std::unordered_map<int, int> dict { {

     { 4, 3 },

     { 0, 2 }, { 2, 2 }, { 6, 2 }, { 8, 2 },

     { 1, 1 }, { 3, 1 }, { 5, 1 }, { 7, 1 }

     }...

   See more on stackoverflow

7. www.geeksforgeeks.org › compiler-design-slr1Compiler Design SLR(1) Parser Using Python - GeeksforGeeks

   www.geeksforgeeks.org › compiler-design-slr1

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   Sep 5, 2022 · C) generateStates. In this function we are starting with GOTO computation. “statesDict” is a dictionary that stores all the states and is used as a global variable. We iterate over the statesDict till new states are getting added to it. We call the compute_GOTO() function on each added state only once. D) compute_GOTO

8. devguide.python.org › internals › compilerCompiler design - Python Developer's Guide

   devguide.python.org › internals › compiler

   • Cached

   This function does both the conversion of the AST to a CFG and outputting final bytecode from the CFG. The AST to CFG step is handled mostly by two functions called by _PyAST_Compile(); _PySymtable_Build() and compiler_mod() . The former is in Python/symtable.c while the latter is Python/compile.c.

9. python.land › python-data-types › dictionariesPython Dictionary: How To Create And Use, With Examples

   python.land › python-data-types › dictionaries

   • Cached

   Jul 14, 2023 · The dict() function builds a dictionary from a sequence or list of key-value pairs ( tuples ): >>> dict( [ ('Jack', '070-02222748'), ('Pete', '010-2488634'), ('Eric', '06-10101010') ]) {'Jack': '070-02222748', 'Pete': '010-2488634', 'Eric': '06-10101010'}