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csHjavaA-2019

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read text files

bookingDate

demo: read text file, use substring

This is a demonstration program, it will show:

How to read a list of values from a text file

How to use substring to select some letters from a text value

constructs used

the program will use the following constructs

file handling

open file

read file

close file

data structure

• string array (to store the values from the file)

control structure

fixed loop using index (to repeat actions for each value in the file / array)

if conditional

substring function

startswith function

substring basics

substring is used to make a new string value by using a defined section of the original string

substring is a string function

the function uses two parameters to define the start and end of the section

in this example the first 5 characters of a message are used to display a single word

H is at position 0 in the string, o is at position 4

the 1st parameter for substring is the position of the 1st character

the 2nd parameter for substring is the (position of the last character) + 1

in this example the last 6 characters of a message are used

you can select a substring anywhere in the text: beginning, middle or end

notice that the ! is in position 11 and the length of the string is 12 characters.

in this example the first character of each variable are used to store initials

choosing a single character needs consecutive positions, in this case 0 and 1

Input requirements

Sample data from file

output requirements

Display full booking list

Bookings on the first day of the month

Bookings in April

design: main steps

code: repl project

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