Beginner | Think Python : Solution to Chapter 3 - Functions

Note : My solutions are independent of the solutions provided by the author. Just an info.

I tried to be a bit flexible with the solution by adding arguments, which allows variations in the number of columns and spacing between “+” and “-”.

Difficulty: I tried to replicate the exact grid but the spacing was quite confusing for me. If you have an idea, do reference your solution. Thanks.

Possible alternative

I was itching to use Python’s syntax for iterations since I do have a programming background knowledge, but I decided to stick with the timeline of the book. But once you complete the recursion & iteration chapter, I would recommend you redo this exercise by using your newly gained knowledge. Additionally, it would simply be another way to confirm your understanding on iterations.

Interesting point

The concept of passing a function as an argument

Solution

If you have any questions regarding the thought process, do not hesitate to ask. See you in the next chapter!

"""
Exercise 3.3. Python provides a built-in function called len that returns the length of a string, so
the value of len("allen") is 5.
Write a function named right_justify that takes a string named s as a parameter and prints the
string with enough leading spaces so that the last letter of the string is in column 70 of the display.
"""


def right_justify(s):
    print((" " * 70) + s)

# right_justify("allen")


"""
Exercise 3.4. A function object is a value you can assign to a variable or pass as an argument. For
example, do_twice is a function that takes a function object as an argument and calls it twice:
def do_twice(f):
f()
f()
Here’s an example that uses do_twice to call a function named print_spam twice.
def print_spam():
print 'spam'
do_twice(print_spam)
"""


def do_four(fn, value):
    fn(value)
    fn(value)
    fn(value)
    fn(value)


#do_four(print, "My name is Comfort Ajala")


"""
Exercise 3.5. This exercise can be done using only the statements and other features we have learned
so far.
Write a function that draws a grid like the following:
+ - - - - + - - - - +
|         |         |
|         |         |
|         |         |
|         |         |
+ - - - - + - - - - +
|         |         |
|         |         |
|         |         |
|         |         |
+ - - - - + - - - - +
"""


def do_four_with_two_arg(fn, valueone, valuetwo):
    fn(valueone, valuetwo)
    fn(valueone, valuetwo)
    fn(valueone, valuetwo)
    fn(valueone, valuetwo)


def print_grid_head(spacing, col_number):
    rep = " - " * spacing + "+"
    print("+", rep * col_number)


def print_grid_line(count, col_number):
    rep = "   " * count + "|"
    print("|", rep * col_number)


def generate_grid(spacing, col_number):
    print_grid_head(spacing, col_number)
    do_four_with_two_arg(print_grid_line, spacing, col_number)
    print_grid_head(spacing, col_number)
    do_four_with_two_arg(print_grid_line, spacing, col_number)
    print_grid_head(spacing, col_number)


#generate_grid(4, 2)


"""
run: generate_grid(4, 2)
result: 
+  -  -  -  -  +  -  -  -  -  +
|              |              |
|              |              |
|              |              |
|              |              |
+  -  -  -  -  +  -  -  -  -  +
|              |              |
|              |              |
|              |              |
|              |              |
+  -  -  -  -  +  -  -  -  -  +
"""
# Write a function that draws a similar grid with four rows and four columns.


def generate_four_rows_for_columns(repfn, spacing, col_number):
    print_grid_head(spacing, col_number)
    repfn(print_grid_line, spacing, col_number)
    print_grid_head(spacing, col_number)
    repfn(print_grid_line, spacing, col_number)
    print_grid_head(spacing, col_number)
    repfn(print_grid_line, spacing, col_number)
    print_grid_head(spacing, col_number)
    repfn(print_grid_line, spacing, col_number)
    print_grid_head(spacing, col_number)


#generate_four_rows_for_columns(do_four_with_two_arg, 4, 4)

"""
run: generate_four_rows_for_columns(do_four_with_two_arg, 4, 4)
result:
+  -  -  -  - + -  -  -  - + -  -  -  - + -  -  -  - +
|             |            |            |            |
|             |            |            |            |
|             |            |            |            |
|             |            |            |            |
+  -  -  -  - + -  -  -  - + -  -  -  - + -  -  -  - +
|             |            |            |            |
|             |            |            |            |
|             |            |            |            |
|             |            |            |            |
+  -  -  -  - + -  -  -  - + -  -  -  - + -  -  -  - +
|             |            |            |            |
|             |            |            |            |
|             |            |            |            |
|             |            |            |            |
+  -  -  -  - + -  -  -  - + -  -  -  - + -  -  -  - +
|             |            |            |            |
|             |            |            |            |
|             |            |            |            |
|             |            |            |            |
+  -  -  -  - + -  -  -  - + -  -  -  - + -  -  -  - +
"""