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Articles on Trending Technologies
Technical articles with clear explanations and examples
How to find the column means if some columns are categorical in R data frame?
To find the column means if some columns are categorical in R data frame, we can follow the below steps −First of all, create a data frame.Then, use numcolwise function from plyr package to find the column means ifsome columns are categorical.Example 1Create the data frameLet’s create a data frame as shown below −Grp
Read MoreConvert list with varying number of elements into a data frame.
To convert list with varying number of elements into a data frame in R, we can use stri_list2matrix function of stringi package along with as.data.frame function.For Example, if we have a list called LIST that contains varying number of elements then we can convert it into a data frame by using the below mentioned command −as.data.frame(t(stri_list2matrix(LIST)))Example 1Following snippet creates a sample list −List1
Read MoreWhat is Stack Allocation of Procedure Calls?
In stack allocation, it can analyze how the memory is allocated at runtime when a procedure is called & when the value from the procedure is returned.Passing Parameter to Procedure (param x)− When actual parameter x is passed to the procedure, it will be pushed into the stack, i.e., push (x).∴ param(x) refers to push (x) which refers to decrementing of the top pointer from N + 1 to N and x will be pushed onto the stack.∴ The following statements will be executed.top = top – 1*top = x or 0[top] = xHere 0[top] means 0 offsets from the ...
Read MoreWhat is Implementation of Simple Stack Allocation Scheme
Stack Allocation scheme is the simplest Run-Time Storage Management Technique. The storage is allocated sequentially in the stack beginning at one end. Storage should be freed in the reverse order of allocation so that a block of storage being released is always at the top of the stack.A program consists of data and procedures. On execution of each procedure, some amount of memory is occupied, which has information regarding the procedure, i.e., its actual parameters, number of arguments, return address, return values & local data, etc. That part of memory is the Activation Record of that procedure.Activation RecordAn Activation Record ...
Read MoreHow to multiply vector values in sequence with matrix columns in R?
To multiply vector values in sequence with matrix columns in R, we can follow the below steps −First of all, create a matrix.Then, create a vector.After that, use t function for transpose and multiplication sign * to multiply vector values in sequence with matrix columns.ExampleCreate the data frameLet’s create a data frame as shown below −M
Read MoreWhat is Heap Allocation?
Heap allocation is the most flexible allocation scheme. Allocation and deallocation of memory can be done at any time and any place depending upon the user's requirement. Heap allocation is used to allocate memory to the variables dynamically and when the variables are no more used then claim it back.Heap management is specialized in data structure theory. There is generally some time and space overhead associated with heap manager. For efficiency reasons, it may be useful to handle small activation records of a particular size as a special case, as follows −For each size of interest, keep the linked list ...
Read MoreWhat is Stack Allocation?
The stack allocation is a runtime storage management technique. The activation records are pushed and popped as activations begin and end respectively.Storage for the locals in each call of the procedure is contained in the activation record for that call. Thus, locals are bound to fresh storage in each activation, because a new activation record is pushed onto the stack when the call is made.It can be determined the size of the variables at a run time & hence local variables can have different storage locations & different values during various activations. Suppose that the registered top marks the top ...
Read MoreWhat is Static Allocation?
It is the simplest allocation scheme in which allocation of data objects is done at compile time because the size of every data item can be determined by the compiler. The main function of static allocation is to bind data items to a particular memory location. The static memory allocation procedure consists of determining the size of the instruction and data space.Recursive Subprogram and Arrays of adjustable length are not permitted in a language. In static allocation, the compiler can decide the amount of storage needed by each data object. Thus, it becomes easy for a compiler to find the ...
Read MoreDescribe the issues in a programming language design that affects storage management?
There are various issues in programming language design that affect the utilization of storage by a running program. There are several elements to which storage must be allocated to execute the object program. Storage space is majorly required for object programs and user-defined data structures, variables, and constants. There is also a need for storage space for procedure linkage information, temporaries required for expression evaluation, and parameter passing.There are the different ways in which various programming languages arrange space for object program are −Static storage allocation− It is the simplest allocation scheme in which allocation of data objects is done ...
Read MoreHow to find the frequency of each value in an R data frame?
To find the frequency of each value in an R data frame, we can use table function along with unlist function.For Example, if we have a data frame called df and we want to find the frequency of each value in df then we can use the below command −table(unlist(df))Example 1Following snippet creates a sample data frame −x1
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