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Articles on Trending Technologies
Technical articles with clear explanations and examples
What is factors which affect the implementation of programming language?
Some factors affect the implementation of programming languages which are as follows −Scope − The scope of a declaration is that portion of a program where that declaration is applied. The implementation mechanism may be different for different languages. Scope rules for each language determine how to go from the declaration of the name. The usage of a name in a procedure is local if it is within the scope of a declaration within that procedure otherwise the usage is non-local. According to the scope of variables in a particular language, storage management is implemented.Lifetime of variable− The lifetime of ...
Read MoreHow to convert alphabets to numbers in data.table object in R?
To convert alphabets to numbers in data.table object in R, we can follow the below steps −First of all, create a data.table object.Then, use mutate_each function of dplyr package along with chartr function to convert alphabets to numbers.ExampleCreate the data.table objectLet’s create a data.table object as shown below −library(data.table) v1
Read MoreWhat is role of Run-time Storage Management in compiler design?
The compiler demands a block of memory for the operating system. The compiler utilizes this block of memory executing the compiled program. This block of memory is called storage management. One of the important tasks that a compiler must perform is to allocate the resources of the target machine to represent the data objects that are being manipulated by the source program.A compiler must decide the runtime representation of the data objects in the source program. In the source program, runtime representations of the data objects, such as integers and real variables, usually take the form of equivalent data objects ...
Read MoreWhat is two array representations in the symbol table?
Symbol Table is a data structure that supports an effective and efficient way of storing information about various names appearing in the source program. These names are used in the source code to identify the different program elements, like a variable, constants, procedures, and the labels of statements.The symbol table is searched each time a name is encountered in the source text. When a new name or new data about an existing name is found, the content of the symbol table modifies.Therefore, the symbol table must have an efficient mechanism for accessing the data held in the table also for ...
Read MoreHow to find the percentage of values that lie within a range in R data frame column?
To find the percentage of values that lie within a range in R data frame column, we can follow the below steps −First of all, create a data frame.Then, use sum function along with extreme values for range and length function to find the percentage of values that lie within that range.ExampleCreate the data frameLet’s create a data frame as shown below −Var
Read MoreHow to find the total by year column in an R data frame?
To find the total by year column in an R data frame, we can use aggregate function with sum function.For Example, if we have a data frame called df that contains a year colmn say Year and a numerical column say Demand then we can find the total Demand by Year with the help of command given below −aggregate(df["Demand"],by=df["Year"],sum)Example 1Following snippet creates a sample data frame −Year
Read MoreVerifying whether the string id * id + id is accepted by a given grammar using SLR parsingnConsider the SLR parsing table for the GrammarnE → E + TnE → TnT → T ∗ FnT → FnF → (E)nF → idnCheck whether the string id * id + id is accepted or not by using the SLR parsing table constructed in the example.
Problem Statement Verifying whether the string id * id + id is accepted by a given grammar using SLR parsingConsider the SLR parsing table for the GrammarE → E + TE → TT → T ∗ FT → FF → (E)F → idCheck whether the string id * id + id is accepted or not by using the SLR parsing table constructed in the example. SolutionInitially, LR Parser in state 0.Put $ at the end of the string, i.e., id * id + id $.StackInput StringReason0id ∗ ...
Read MoreHow to standardize selected columns in data.table object in R?
To standardize selected columns in data.table object in R, we can follow the below steps −First of all, create a data.table object.Then, use scale function and cbind function with subsetting to standardize selected columns.ExampleCreate the data.table objectLet’s create a data.table object as shown below −library(data.table) var1
Read MoreHow to save a matrix as CSV file using R?
To save a matrix as CSV file using R, we can use write.matrix function of MASS package. For Example, if we have a matrix called M and we want to save it as CSV file then we can use the below mentioned command −write.matrix(M,file="Mat.csv")ExampleFollowing snippet creates a sample matrix −M
Read MoreWhat is an Activation Record?
An Activation Record is a data structure that is activated/ created when a procedure/function is invoked, and it includes the following data about the function.Activation Record in 'C' language consist ofActual ParametersNumber of ArgumentsReturn AddressReturn ValueOld Stack Pointer (SP)Local Data in a function or procedureHere, Old SP stores the value of stack pointer of Activation Record of procedure which has called this procedure which leads to the generation of this Activation Record, i.e., It is a pointer to the activation record of the caller.In Stack Allocation Scheme, when procedure A calls Procedure B, the activation record for B will be ...
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