Tutorial 7

1. Text file practice

Write a module containing three functions. When run, the module should prompt the user for a filename and a number of lines (let's refer to it as n) and then call each function in turn with these parameters.

a. The function head1 should return a list containing the first n lines of the file using read.

b. The function head2 should return a list containing the first n lines of the file using readline.

c. The function head3 should return a list containing the first n lines of the file using readlines.

Make a test at the bottom to show the output of running the module, it might look like this:

```plaintext

   Name of file to test with: pooh.txt
   Number of lines to display: 3

   head1 says the first 3 lines are:
   The more it snows
     (Tiddely pom),
   The more it goes

   head2 says the first 3 lines are:
   The more it snows
     (Tiddely pom),
   The more it goes

   head3 says the first 3 lines are:
   The more it snows
     (Tiddely pom),
   The more it goes

```

Here is a short file to test with [pooh.txt](90_pooh.txt)

2. Making it space efficient

Since the file could be very long you will not want to read the whole thing into memory as a list of lines... Modify one of your head functions from the previous questions so that it only loads the number of lines needed (only one of them will work).

Here is a short file to test with pooh.txt

3. Trilobite data

Follow along with the instructor to complete the functions used to work with the trilobite data. Make sure you have working versions of...

a. open_trilobite_data()

b. calculate_diversity()

c. write_trilobite_data()