|
| 1 | +# exercise 9.2.3 from unit 9 |
| 2 | +''' |
| 3 | +Write a function called who_is_missing defined as follows: |
| 4 | + |
| 5 | +def who_is_missing(file_name): |
| 6 | +The function accepts as a parameter a path to a text file (string). |
| 7 | +The file we return is passed as an argument and contains a list of integers from 1 to some n, which are not sorted, separated by commas, when one of the numbers in the sequence disappears (that is, missing from the sorted list). |
| 8 | + |
| 9 | +The operation of the who_is_missing function: |
| 10 | +A. The function returns the missing number in the sequence (int). |
| 11 | +B. The function writes the missing number in sequence to a new file called found.txt. |
| 12 | + |
| 13 | +An example of an input file and the execution of the who_is_missing function |
| 14 | +A file called findMe.txt: |
| 15 | + |
| 16 | +8,1,9,7,4,6,3,2 |
| 17 | +Running the who_is_missing function on the findMe.txt file: |
| 18 | + |
| 19 | +>>> who_is_missing("c:\findMe.txt") |
| 20 | +5 |
| 21 | +After the above run of the who_is_missing function, a new file called found.txt is created: |
| 22 | + |
| 23 | +5 |
| 24 | +''' |
| 25 | + |
| 26 | +def who_is_missing(file_name): |
| 27 | + # Read the file and extract the numbers |
| 28 | + with open(file_name, 'r') as f: |
| 29 | + numbers = [int(num) for num in f.read().split(',')] |
| 30 | + |
| 31 | + # Find the missing number |
| 32 | + expected_sum = sum(range(1, len(numbers) + 1)) |
| 33 | + actual_sum = sum(numbers) |
| 34 | + missing_number = expected_sum - actual_sum |
| 35 | + |
| 36 | + # Write the missing number to a new file |
| 37 | + with open('found.txt', 'w') as f: |
| 38 | + f.write(str(missing_number)) |
| 39 | + |
| 40 | + return missing_number |
| 41 | + |
| 42 | +def main(): |
| 43 | + result = who_is_missing("c:\findMe.txt") |
| 44 | + print(result) |
| 45 | + |
| 46 | +if __name__ == "__main__": |
| 47 | + main() |
0 commit comments