Lecture 13 — Exercises¶

Solutions to the problems below must be sent to Submitty for grading. A separate file must submitted for each problem. Solutions must be submitted by 4 pm on Tuesday, October 17.

Given the file census_data.txt:

Line 1 |Location    2000    2011
Line 2 |New York State  18,976,811  19,378,102
Line 3 |New York City   8,008,686   8,175,133
Line 4 |

What is the output of the following code? (Note: the line numbers and the “|” are not actually in the file, they are just there to show that the contents of the 4 lines.)

f = open("census_data.txt")
line1 = f.readline()
line1 = line1.strip()
line2 = f.read()
line3 = f.readline()
print(line1)
print(line2)
print(line3)
f.close()
f = open("census_data.txt")
s = f.read()
line_list = s.split('\n')
print(len(line_list))
line_list = s.strip().split('\n')
print(len(line_list))

Submit your output as a text file.

Given a file containing test scores, one per line, we want to have a new file that contains the scores in increasing order. To do this, write a Python program that asks the user for two file name strings, one for the input scores and the second for the output, sorted scores. The program should open the first file (to read), read the scores, sort them, open the second file (to write), and output to this file the scores in increasing order. There should be one score per line, with the index on each line.

As an example, suppose the input file is scores.txt and it contains
```
75
98
75
100
21
66
83
15
```
then running your program should look like (in Wing IDE):
```
Enter the scores file: scores.txt
scores.txt
Enter the output file: scores_sorted.txt
scores_sorted.txt
```
When you look at the contents of scores_sorted.txt you should see
```
0:  15
1:  21
2:  66
3:  75
4:  75
5:  83
6:  98
7: 100
```
(Output the indices using two integer spaces {:2d} and the scores using three {:3d}.) You only need to submit the Python file. We will test with the example above and with a new file you have not seen.