Question

Python3 please use while loop to solve this question,specific information is on the graph

Question 2 - 15 marks Write the function read_file_center50 (filename). The function returns a list of 50 strings that are at the center of the file. A file has n lines, then is the center. A list of length 50 is returned, where the first line is 25 and the last line is 2 + 25. If the file has n < 50 lines, then only those lines are returned. If there are lines in the file, empty list object is returned no an If the file cannot be opened because it does not exist, you must catch the FileNotFoundError object and throw a new exception FileNotFoundError with the contents of the exception being the filename. Any other exception for failure to open a file is not caught If the parameter filename is not a string type, then a TypeError exception is thrown with the contents of the exception being a string "parameter filename is not a string" Examples the file has 200 lines. lines 75 - 124 are returned the file has 201 lines. lines 75 - 124 are returned (n is an odd number) the file has 202 lines. lines 76 - 125 are returned the file has 700 lines. lines 325 - 374 are returned the file has 10 lines. lines 1 - 10 are returned See appendix for open(), close(), readlines() and isinstance() to support this question Restrictions Only Allowed: while loops, if statements, function len(), type(), isinstance(), list method append () string method split(), format (). keywords elif, else, return, break, continue, def, self, None, try, raise, except, is, import sys, and any arithmetic or boolean comparison operators, any file methods from the reference page Remember: Do not use a for loop, do not use the in keyword, do not use the with keyword, do not use enumerate, do not use slices or slicing e.g. [1:], do not use lambda functions e.g. sorted(). Marks will be deducted

Answer 1

Screenshot

Program

Ouick Launch (Ct dFileCertre30RcodinPython Miciouct Viul Studo View Pmjert Rld Debun Team Toels deepthiongaratu D File Fit Tart Analyre Winciow Hele Atach O bu Ary CPU ythanp x #for file path exist check ECAWINDOWSastem3emdee paraneter filenare is nota string import os #Function to get number of 12 def get_num_lines (filename): with open(filename) as fress any key to continue lines fp.readlines () fp.close return len(lines) #Function to read file lines #which append all lines in def read_file less50(filenan with open(filename) as f line=fp.readline ( ).r 1st.append(1line) while line: line fp.readline 1st.append(line fp.close) #function to get centre 50 lines of a file Ready Ln 33 Col 13 Ch 13 f Add to Sou Control e OTyce here to search. 14-06-201

#for file path exist check
import os
#Function to get number of line in the file
def get_num_lines(filename):
    with open(filename) as fp:
        lines=fp.readlines()
        fp.close()
        return len(lines)
#Function to read file lines if the count of lines less than 50
#which append all lines in the list
def read_file_less50(filename,lst):
    with open(filename) as fp:
        line=fp.readline().rstrip("\n\r")
        lst.append(line)
        while line:
            line=fp.readline().rstrip("\n\r")
            lst.append(line)
    fp.close()
#function to get middle 50 lines of a file
def read_file_more50(filename,num,lst):
    num=num/2
    start=num-25
    end=num+25
    cnt=0
    with open(filename) as fp:
        line=fp.readline().rstrip("\n\r")
        cnt+=1
        while line:
            line=fp.readline().rstrip("\n\r")
            cnt+=1
            if(cnt>=start and cnt<end):
                lst.append(line)
    fp.close()
#function for getting file data  
def read_file_middle50(filename):
    try:
        #for file lines
        lst=[]
        #Check file name is a string
        #Otherwise TypeError exception raise
        if(isinstance(filename,str)):
            #Check file exist
            #Otherwise file not found exception
            if(os.path.exists(filename)):
                #Get number of line in the given file
                num_lines=get_num_lines(filename)
                #Check empty file
                #return empty list
                if(num_lines==0):
                    return lst
                #If line count<50 return all lines
                elif(num_lines<50):
                    read_file_less50(filename,lst)
                    return lst
                #If line count>50 return middle 50 lines
                else:
                    read_file_more50(filename,num_lines,lst)
                    return lst
            #file not found error raise
            else:
                raise FileNotFoundError(filename+" file not found!!!")
        #Not string error raise
        else:
            raise TypeError("parameter filename is not a string")
    #Exceptions
    except TypeError as ex:
        print(ex)
    except FileNotFoundError as ex:
        print(ex)
#Test part
read_file_middle50(10)
read_file_middle50("test.txt")
print(read_file_middle50("C:/Users/deept/Desktop/test.txt"))

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output

parameter filename is not a string
test.txt file not found!!!
['24', '25', '26', '27', '28', '30', '31', '32', '33', '34', '35', '36', '37', '38', '39', '40', '41', '42', '43', '44', '45', '46', '47', '48', '50', '51', '52', '53', '54', '55', '56', '57', '58', '59', '60', '61', '62', '63', '64', '65', '66', '67', '68', '69', '70', '71', '72', '73', '74', '75']

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Program Screenshot

path exist check import os Function to get number of line in the file def get_num_lincs (filename) with 1ines fp.readlines fp.close) #Function to read file 1ines if the court of 11nes 1ess than 5e #which append all lines in the list def read file less5e(filename, lst): with inc-fo.ceadline(),strip("\e\r") 1st.append (line) whil 1inesfo.read1ine().rstrip("\n\r" 1st.append(line) fp.clese( entre 50 lines ile def read file more 50r filename.num.1st): num-num/ 25 endnum-2s cnt with 1ieeto readline().cstrin("\n)r") cnt+-1 whi 1inc-fp.readline (.rstrip("\n\r") cnt+-1 if(cnt-start and cntend): append (1ine) fp.close #function for gctting file data det file centerS0(filename): #for file lines Hcheck filc name is a string #otherwise ypetrror exception raise str)): +Check f4l exist Ctherwise rile nat raund exception it be of 14ne in the eiven file num 11nes-get_num_1ines (filen ame) if(num 1ines= 0) < return all 1ines elif(numlines<se) : lese 5@ (filoname, let) raad 1t It ane count>50 return cemter 50 ines clse e ad file morerfilename.nun 1ines,1st) t tound erro #riis n raise else: drrer (fi1en+ " fil rl foutud Y Not atring ercon ro:se. lsas