import sys

def read$\_$book$($filename$)$:

contents $=[]$

with open$($filename$)$ as book:

for line in book.readlines$()$:

line $=$ line.strip$(\text{'}$

$\text{'})$ # Strip off the trailing new$-$line character

line $=$ line.split$(\text{'}|\text{'})$ # Split the line into separate fields

line$[1]=$ int$($line$[1])$

contents.append$($line$)$

contents.sort$($key$=$lambda x: x$[1])$

return contents

def find$\_$longest$\_$line$($contents$)$:

long$\_$line $=["",0]$

for i$,$ line in enumerate$($contents$)$:

if len$($line$[0])>$ len$($long$\_$line$[0])$:

long$\_$line $=[$line$[0],$i$]$

return long$\_$line

def calculate$\_$average$\_$length$($contents$)$:

total$\_$length $=$ sum$($len$($line$[0])$ for line in contents$)$

average$\_$length $=$ round$($total$\_$length $/$ len$($contents$))$

return average$\_$length

def write$\_$results$($book$\_$name, contents$)$:

filename$=$ f$"\{$filename$\}\_$book.txt$"$

with open$("$filename$","$w$")$ as summary$\_$file:

summary$\_$file.write$($TTL$+"$

$")$

longest$\_$line$=$ find$\_$longest$\_$line$($contents$)$

summary$\_$file.write$($f$"$ Longest line $(\{$longest$[0]\}))$: $\{$longest$[0]\}|\{$longest$[1]\}$

$")$

average$\_$length $=$ calculate$\_$average$\_$length$($contents$)$

summary$\_$file.write$($f$"$Average length: $\{$average$\_$length$\}$

$")$

for line in contents:

summary$\_$file.write$($f$"\{$line$[0]\}$n$")$

def main$()$:

filename $=$ sys$.$argv$[1][$:$-4]$

contents $=$ read$\_$book$($sys$.$argv$[1])$

write$\_$results$($filename$,$ contents$)$

if $\_\_$name$\_\_=="\_\_$main$\_\_"$:

main$()$

Structure

File

library.py

Input

a text file such as TTC$.$txt

one input file for each book

Output

text file such asTTC$\_$book.txt

one output file for each book

Problem

You$$re an intern at the Library of Congress. You are given a collection of text files where each file corresponds to a book. Each file is named with a three$-$letter code for the book it contains. Examples are like TTC$.$txt$,$ WOO.txt$,$ TTL$.$txt and other names too. There could be many such input files and we may not know how many.

Each line in the file looks like this: one line from the book and the line number, separated by a $\text{'}|.$ For example: $"$It was the best of times, it was the worst of times,"$|1$

You discover though, that the content of each file is scrambled so that the lines are not in order.

Your task is to write a program that reads each of these book files and does a few things:

Find the longest line from the book along with its line number.

Calculate the average length of the lines in the book.

Unscramble the lines of text in order of line number.

Once your program has done that, it needs to save this information in a new file called $\text{'}\_$book.txt$.$ The format would be:

first line is the three$-$letter code

second line is the longest line with line number and content as shown

third line is the average length

lines $4$ to end are the contents of the book in line order

Example Run

As an example, for this input

python$3$ library.py TTL$.$txt

Your code will generate a file named as TTL$\_$book.txt and the first few lines of that output file would look like this:

TTL

Longest line $(14153)$: Ecclesiastes$$Who can fathom the soundless depths?$$two men out of all

Average length: $58$

Twenty Thousand Leagues Under the Seas

An Underwater Tour of the World

JULES VERNE

$[......]$

If there are multiple lines with the same length as the longest, use the line number to decide: the line that appears later is considered as "longest". Round the average to the closest integer.

And that$$s it$!$ You$$ve gathered useful information, unscrambled the text, and written the information to a new file.