Which type of file access jumps directly to a piece of data in the file without having to read all the data that comes before it?
– When you need to access a specific piece of data in a file, it can be time consuming to have to read through all the data that comes before it.
– Often times when you’re trying to access a specific piece of data, you have to read through all the data that comes before it, which can be time consuming and inefficient.
– With direct file access, you can jump directly to the piece of data you need without having to read through everything else. This makes accessing specific pieces of data much faster and easier.
Prerequisites – File system
-When a file is utilized, the information contained inside it is read from the file and loaded into the memory of the computer. The information contained within a file may be accessed in a number of different ways. There are certain systems that only provide a single means of accessing files. Other systems, such as IBM’s, offer several access ways; nevertheless, selecting the appropriate access method for a specific application is a significant challenge that must be overcome during the design phase.
-Sequential Access, Direct Access, and the Sequential Indexing Method are the three methods that may be used to access files inside the computer system.
-The technique of access that is the least complicated is called sequential access. The information included in the file is processed sequentially, beginning with the first record and moving on to the next. This access mechanism is by far the most frequent and is used by editors and compilers, for example, to access files.
The bulk of the actions that may be performed on a file are reads and writes. Read operation – read next – reads the next position of the file and automatically increases the file pointer. The file pointer maintains track of the I/O position. Read operation – read previous – reads the previous position of the file. In a similar manner, with the -write next command, add new information to the end of the file and then switch to the page. Brand fresh content is being written.
The records in the database are accessed one right after the other in a sequential manner.
In the event that we utilize the read instruction, it will advance the pointer by one.
When the write command is executed, memory will be allocated, and the pointer will be moved to the end of the file.
The use of such a technology is acceptable for tape.
-Direct access is another approach that may be used. This method, which is also known as the relative access method, is called direct access. A logical record with a classified length provides the application with the ability to read and write records in a timely manner. in no particular sequence. Because a disk permits random access to any block of files, direct access is based on the disk model of the file. This is because direct access is more efficient. The file is regarded as either a block chain or a numbered record when direct access is being used. As a result, we may begin by reading block 14, then go on to block 59, and finally begin by writing block 17. The sequence in which reading from and writing to a direct access file must be performed is not constrained in any way.
The block number that the user supplies to the operating system is often a relative block number. The first relative block of a file is represented by the number 0, followed by block 1 and so on.
-The indexing serialization technique is an additional file access method that expands upon the sequential access method. This method is built on top of the sequential access method. Using these techniques will result in an index being created for the file. Indexes, much like the index found at the back of a book, include links that navigate the reader to various blocks. First, we search through the index to see whether the record we’re looking for is there, and then, with the assistance of the pointer, we go into the file itself.
The primary draws are:
It operates using a sequential access model.
It exercises control over the pointer by referring to the index.
c. File object
Which one of these is linked to a particular file and makes it possible for the application to interact with that file? a. Filename b. Extension c. File object d. File variable
b. Reading data
The action of extracting data from a file is referred to by what specialized term? a. Retrieving data b. Reading data c. Input data d. Get data
a. Information is written to a file from a variable that is stored in RAM.
What does place when a byte of data is appended to a file? a. Information is written to a file from a variable that is stored in RAM. b. Information is written to a file by copying it from a variable inside the program. c. The data are saved to a file after being copied from the application. d. Information is written to a file by copying it from a file object.
a. Start by opening the file.
Which of these actions results in the establishment of a link between a file and a program? a. Start by opening the file. c. Take a look at the file. c. Handle the file’s processing. d. Exit out of the file.
b. Two (Text and Binary)
How many different kinds of files are there to choose from? a. One b. Two c. Three d. Four a. One b. Two c. Three
A file that has random access may alternatively be referred to as a file that has direct access. a. sequential b. random c. numbered d. text
What kind of file access allows you to skip reading the data that comes before a certain piece of data so that you may get straight to the data you need? a. In Sequence b. At Random c. In Numbers d. In Text
What mode specifier will allow you to open a file but will prevent you from making any changes to the file or writing to it? a. ‘w’ b. ‘r’ c. ‘a’ d. ‘e’
Which mode specifier will overwrite the contents of an existing file with new data if the file does not already exist, but will create the file if it does not already exist? a. ‘w’ b. ‘r’ c. ‘a’ d. ‘e’
customer.write(“Mary Smith”) is the correct answer.
Take for granted that the customer file has a reference to a file object and that the file in question was opened with the ‘w’ mode specifier. How would you add the string “Mary Smith” to the file you’re working on? customer file.write(“Mary Smith”) is the first step. customer.write(‘w’,’Mary Smith’) is the second option. customer.input(“Mary Smith”) is the correct answer. customer.write(“Mary Smith”) is the correct answer.
Which technique will return the contents of the file as a string when a file has been opened with the ‘r’ mode specifier? a. compose b. feed information into c. obtain d. read
Which approach might be used in order to remove certain characters from the terminal portion of a string? a. estrip b. rstrip c. strip d. remove
In order to convert a numeric number into a string, which technique should be utilized? a. str b. value c. num d. chr
Which technique will give you back an empty string if you ask it to read beyond the end of a file after it has already tried to do so? Read (a) and Getline (b) input c., readline d.
c. a sentence that uses try and except
In a computer program, which statement should be used to manage some of the run-time faults that may occur? a. statement of exception b. statement of trying c. statement of trying and excepting d. statement of handling exceptions
If a file with the supplied name already exists when the file is opened, and the file is opened in the “w” mode, then an alert will display on the screen to let you know that the file is being opened in the “w” mode.
Verify if the following statement about reading data from a file is true or false: the data is copied from the file into the program when it is read.
If you close a file, the software and the file will no longer be able to communicate with each other, true or false?
The programmer has the ability to deal with both text and numeric files while using Python. True/False?
If the program attempts to access a file to read but the file does not exist, there is nothing that can be done about it in Python, is that true or false?
If the program tries to divide by zero, then it will throw the ZeroDivisionError exception, depending on whether or not the statement is true.
Which of the following statements about an exception handler is true? An exception handler is a piece of code that is constructed using the try/except statement.
If the final line in a file is not concluded with an n, then the readline method will return the line without a n at the end of it. True or false?
It is possible to write strings directly to a file using the write method; however, numbers must first be transformed into strings before the write method can be used on them. True/False:
It is feasible to design a while loop that checks to see whether the end of a file has been reached, so let’s see if that statement is true or not.
When information is taken from a file and read into a program, that information is taken from the file and copied into the program. When you close a file, the application and the file are no longer able to communicate with one another. If a program is written in Python, and it attempts to read data from a file that does not exist, there is nothing that can be done about it.
Data that has not been translated to text format is included inside a binary file. The information that is saved in a binary file is designed to be readable by only a computer program.
The direct access file operates in a manner that is similar to that of an MP3 player, in which the player always begins playing from the beginning.
In the event that a job must be temporarily halted because a control variable has reached a certain value, what is the correct wording to use? True/False: A file from which data is read is referred to as a “output file,” and this word is often used.
When it has tried to read past the end of a file, the readline function will return an empty string (“”) as its result.