2.2 String manipulation + BASIC FILE HANDLING

Question 1

Define string manipulation

Answer 1

String Manipulation: “The act of manipulating, extracting or changing the characters in a string variable”

Question 2

State the string manipulation commands

Answer 2

string manipulation commands

.length
.upper
.lower
.substring (x, i)
ASC(…)
CHR(…)

Question 3

What does .length mean

Answer 3

.length is used to get the length of a string
Returns the length of a string

length = string.length - if the string was “Hello” then length would be 5

Question 4

What does .upper and .lower mean

Answer 4

.upper and .lower
Used for converting the cases of a string
Returns the string in uppercase and lowercase

Question 5

What deos .substring(x, i) mean

what will output

chars=”Hello”
chars = string.substring (3,1)
print(chars)

Answer 5

substring(x, i)
to get a substring

Returns part of a string, starting at the character of the first parameter and up to (not including) the number of characters in the second parameter

stringname.subString(startingPosition, numberofCharacters)

chars = string.substring (3,1) - index starts at 1

If string was “Hello” then chars would be “I” (lowercase L)

Question 6

what does ASC(…) mean

ascii=ASC(“A”)
print(ascii)
what would output

Answer 6

Ascii conversion
ASC(…)
Returns the ASCII value of a character
ASC(character)
e.g.
ascii=ASC(“A”)
ascii would be 65

Question 7

What does CHR(…) mean

Char = CHR(65)
print(Char)
what would output

Answer 7

Ascii conversion
CHR(…)
Returns the character from the ASCII number

CHR (asciinumber)
Char = CHR(65)
char would be “A”

Question 8

What will this code display

someText=”Computer Science”
print(someText.length
print(someText.substring(3,3)).upper)

Answer 8

Will display:
16 - includes spaces
PUT

Question 9

State the string manipulation commands in python

Answer 9

string manipulation commands in python

.len
.upper()
.lower()
.substring (x, i)
ord(…)
chr(…)

Question 10

what does .len mean

write a program to work out the length of this list
“Hello”

what would be the output

In a high level programming language

Answer 10

Returns the length of a string

string=”Hello”
length = len (string)
print(length)
- if the string was “Hello” then length would be 5

Question 11

what does .upper and .lower mean

write a program which displays the word “Hello” in uppercase and lowercase

In a high level programming language

Answer 11

Returns the string in uppercase or lowercase

ustring = string.upper() -

if the string was “Hello” then ustring would be “HELLO”

lstring = string.lower() -

If the string was “Hello” then lstring would be “hello”

Question 12

what does .substring (x, i) do

write a program which splits “Hello” into a sublist to become “l” - 1st L

In a high level programming language

Answer 12

• substring - Returns part of a string, starting at the character of the first parameter and the ending position in the second parameter

stringname.subString(startingPosition, endingPosition)

string=”Hello”
chars = string[2:3] - index starts at 0

Question 13

what does ord(…) do

Answer 13

ord (…)
Returns the ASCII value of a character

Question 14

Write a program which returns the ASCII value of the character “A” - in a high level programming language
what would the output be

Answer 14

ascii = ord(“A”)
print(ascii)

ord(character)

outuput - 65

Question 15

What does chr(…) do

Answer 15

chr (…) Returns the character from the ASCII number

Question 16

write a program which returns the character from the ascii value “65” - IN A HIGH LEVEL PROGRAMMING LANGUAGE
what would the output be

Answer 16

char = chr(65)
print(char)

output
A

Question 17

what will be the output of this program

someText=”Computer Science”
print(len(someText))
print((someText[3:7].upper())

Answer 17

Program will display

16
PUTE

Question 18

How to write data to a file

Answer 18

Open the file for creating/overwriting or appending to a file

Write data to a file

Close the file

Question 19

What are the stages of reading data from a file

Answer 19

Open the file for reading data

Assign a boolean variable to “false” to indicate the end of the file is not reached

While the end of the file is false and the search item is not found:
Read the file from data
If the data matches what is being searched for, assign the data to variable or output
Check if the end of the file has been reached and assign the Boolean variable to “True”

Close the file

Question 20

In python, what do you write to open a file, with the intention to read from the file

Answer 20

f = open(“characters.txt, “r”)

f - is a variable
The open command takes two parameters:

“characters” - the name of the file to open

“r” - what we want to do with the file e.g. read

Question 21

In python how do you indicate that you have not reached the end of the file

Answer 21

end_of_file = False
or
while not end_of_file:

• end_of_file is a variable

Question 22

In python, what do you write to read a file

Answer 22

f = open(“characters.txt, “r”)

….

name=f.readline().strip()
health=f.readline().strip()

name and health are variables

f - was assigned earlier as being a pointer to characters.txt

.strip() - this strips the new line character - so we just get the name/ the thing we want. the new line character is there, as when writing the file - we were pressing enter - the enter is stored as a character - to signify a new line

Question 23

In python how do you close the file

Answer 23

f.close()

f is just a variable
f is just pointing to characters.txt

f is the thing connecting our program to our text file

Question 24

In python how do you open a file, with the intention to write

Answer 24

f = open(“characters.txt”, “a”)

The open command takes two parameters

“characters.txt” the name of the file we want to connect to
“a” - means we want to append (add) to the end of the file

“w” - this would create a new file or overwrite contents of an existing file

Question 25

How do we show in python that we want to start a new line

Answer 25

e.g.
“hello” \n - means start a new line

Question 26

In python, what do you do to write to a file

Answer 26

f.write(name+”\n”)
f.write(health+”\n”)

name and health are variables

Question 27

In OCR Exam Reference language how do you open a file

Answer 27

myFile = open(“sample.txt”)

myFile is a variable

Question 28

In OCR Exam Reference language how do you close a file

Answer 28

myFile.close()

myFile is a variable

Question 29

In OCR Exam Reference language how do you read a line from the text file

Answer 29

x = myFile.readLine()

x - program assigns x to be the first line of sample.txt

.readLine - is the read line command

Question 30

In OCR Exam Reference language how do you write to a file

Answer 30

myFile.writeLine(“Hello World”

Question 31

In OCR Exam Reference language how do you determine the end of the file

Answer 31

myFile.endOfFile()

endOfFile() is used to determine the end of the line/

Question 32

In OCR Exam Reference language how do you determine you are not at the end of the file

Answer 32

NOT myFile.endOfFile()

myFile - is a variable

Question 33

What is data dependency

Answer 33

Data dependency is when a program requires the items from the text file to be in a very certain order.

Question 34

what is sql used for

Answer 34

SQL is used to create, delete, modify and manipulate records in a database

Question 35

basic commands of sql

Answer 35

SELECT – (tells us) which fields (are) to be returned. (An asterisk * can be used to indicate all fields)

FROM – (tells us which table of the database do we want to extract information from) which table. Databases can have more than one table, each with their own unique name

WHERE – records meet a condition. The keyword LIKE can be used as a wildcard.

Question 36

what is an array

Answer 36

An array is a static number of related data items that are stored together in the same memory space

Each data item has the same data type

Question 37

HOW IS A PARTICULAR ITEM IN A LIST FOUND

Answer 37

The particular data item (element) is found using its index

Question 38

TWO TYPES OF SUB PROGRAMS

Answer 38

Procedures

Carry out a task

Provide structure to code

Functions

Carry out a task AND return a value

Create reusable program components

Question 39

ADV. OF USING SUB PROGRAMS

Answer 39

he program is easier to write

The program is easier to debug

We are creating reusable components

Functions could be gathered together into a library for easy reuse across multiple programs

An example is import random

This imports the “random” library of functions into our program so we can use them.

The program is easier to test (if we block our program into sub programs, - this is because we can test each procedure or function individually on its own and when we know it works, we can put it into a larger overall program)

Question 40

what are subroutines

Answer 40

Larger programs are developed as a set of sub-programs called subroutines

Question 41

Examples of situations when you might want to generate a random number

Answer 41

Simulating the roll of a dice

Generating a random set of co-ordinates

Gambling simulations

National lottery program

Quiz programs (selection a random question from a list of questions)

Cryptography