Question

Write a Python program (question2.py) that reads from a file called “input.txt” numbers in [1,39] separated in by commas. The numbers are in [1-99]. The program will then convert each number to a possible Roman Numeral equivalent, and print it on the screen. Remember, I is 1, V is 5, X is 10

For example, if the input is: 23, 11 the output is: XXIII, XI.

ROMAN NUMERALS CHART 1 TO 100 69 LXIX 11 2 11 3 III 4 IV 5 V 6 VI 1 VII 8 VIII 9 IX 10 X 11 XI 12 XII 13 XIII 14 XIV 15 XV 16 XVI 17 XVII 18 XVIII 19 XIX 20 XX 21 XXI 41 XLI 22 XXII 42 XLII 23 XXIII 43 XLIII 24 XXIV 44 XLIV 25 XXV 45 XLV 26 XXVI 46 XLVI 27 XXVII 47 XLVII 28 XXVIII 48 XLVIII 29 XXIX 49 XLIX 30 XXX 50 L 31 XXXI 51 UI 32 XXXII 52 LII 33 XXXIII 53 LIII 34 XXXIV 54 LIV 35 XXXV 55 LV 36 XXXVI 56 LVI 37 XXXVII 57 LVII 38 XXXVIII 58 LVIII 39 XXXIX 59 LIX 40 XL 60 LX 61 LXI 81 LXXXI 62 LXII 82 LXXXII 63 LXIII 83 LXXXIII 64 LXIV 84 LXXXIV 65 LXV 85 LXXXV 66 LXVI 86 LXXXVI 67 LXVII 87 LXXXVII 68 LXVIII 88 LXXXVIII 89 LXXXIX 70 LXX 90 XC 71 LXXI 91 XCI 12 LXXII 92 XCII 73 LXXIII 93 XCIII 74 LXXIV 94 XCIV 75 LXXV 95 XCV 76 LXXVI 96 XCVI 77 LXXVII 97 XCVII 78 LXXVIII 98 XCVIII 79 LXXIX 99 XCIX 80 LXXX 100 C

Answer 1

CODE

f = open("input.txt")
data = f.read()
# split the data using comma as seperator
# convert string list into integers list using map and lambda
numbers = map(lambda x: int(x),data.split(","))
# map of where all changes happens in roman numbers
roman_map = [(100,"C"),(90,"XC"),(50,"L"),(40,"XL"),(10,"X"),(9,"IX"),(5,"V"),(4,"IV"),(1,"I")]

# process numbers one by one
for number in numbers:
    #print number =>, here end is not new line but space
    print(number, "=>",end=" ")
    # process all factors in roman numerals
    # 0th element of each x is integer and 1st is roman numerals
    for x in roman_map:
        # we can get number of times the roman character should be
        # printed by dividing our number with the factor
        # if it's 0 then nothing will be printed
        count = number // x[0]
        # print the character as times as we calculated
        print(x[1]*count,end="")
        # reduce the this count times the factor as we processed it
        number -= (x[0]*count)
    # lets print a new line for next result
    print()

Explanation

I've provided most of the explanation in the code as comments but I'll give a general working logic here too.

The program starts by reading input.txt

by using read method it reads all data of file and store it into data variable.

Now using split method we split it into a list of strings.

Now using map we process each strings and convert it to integer datatype as specified in our inline lambda function.

Now to convert the number into roman numbers first we need analyse how number or character pattern changes in roman numerical system.Since our question only points us to do the calculations for numbers till 100 we only going to do that.

First change of pattern occurs in number 4

that's

1 - I

2 - II

3 - III

4 - IV

Since the beginning of number 1 the number starts to show variation in pattern and introduces new character V in it.

So we need to take a note of this.

So we store these kind of "changing points and store their corresponding roman numerical characters in a list of tuples with first element as integer and 2nd one as corresponding roman number, for easy lookup.

roman_map = [(100,"C"),(90,"XC"),(50,"L"),(40,"XL"),(10,"X"),(9,"IX"),(5,"V"),(4,"IV"),(1,"I")]

Note: since our question specifies till 100, we're only going to analyse till 100.

Now as we got our guiding map lets process all numbers in the numbers list by looping

inside loop we prints the "number =>" with end character as a specifier.If didn't specify this it'll lead to printing a newline.

now in the inner loop what we going to do is we iterate through our roman_map's elements.

We can get number of times the roman character should be printed by dividing our number with the changing point integer.

Since this division is integer division (// operator), if the number is greater than our number it will produce zero and no character would be printed.

Since in Python "string" * integer will print the "string" number of times as specified in the multiplying number,we'll also use that trick to print our roman numeral characters as many times we need to print.

print(x[1]*count,end="")

x[1] is our roman numerals and count is what we calculated.

now we subtract this count times changing point as we might have somemore integers left and we don't need to process the already processed part.

and same process is continued.

Screenshots and Output