loop_1

# Demonstrate various methods to create a list of numbers in Python.
# Copyright 2023 Roland Richter                           [Mu: Python 3]

# If you have to create a list which holds numbers 0, 40, 80, ..., 400,
# there are several methods to do it:.
# 1. You could simple write a list with all items in it:
nums_a = [0, 40, 80, 120, 160, 200, 240, 280, 320, 360, 400]

# ... really tedious typing, isn't it? There are better ways.
# 2. The second way is still a bit tedious:
nums_b = []             # Create an empty list, then ...
num = 0
while num <= 400:       # ... (until 400 is reached)
    nums_b.append(num)  # ... start appending numbers: first 0, ...
    num += 40           # ... then 40, 80, and so on.

# Now, open a handbook such as
# https://www.w3schools.com/python/python_strings.asp
# and start to FIX my code; but ONLY code inside ↓ / ↑ lines!

# 3. Python provides another way to loop through numbers:
# the "for" loop with the range(start, stop, step) function, where
# start is the integer to start the iteration with,
# stop is the integer to stop with (not included),
# step is the integer specifying the increment.
# A common source of errors is the fact that stop is NOT included.
# FIX the numbers in "range" to create all numbers 0, 40, ... 400:
# ↓---------↓---------↓---------↓---------↓---------↓---------↓
nums_c = []
for num in range(0, 400, 40):
    nums_c.append(num)
# ↑---------↑---------↑---------↑---------↑---------↑---------↑

# 4. Two of the arguments of range(start, stop, step) are optional:
# start is the integer to start with -- optional (default: 0),
# stop is the integer to stop with (not included) -- required,
# step is specifying the increment -- optional (default: 1).
# So, writing "for num in range(10)" means "for num in range(0, 10, 1)",
# which is another way of saying "loop over 10 numbers, from 0 to 9".
# FIX the numbers in "range" to create all numbers 0, 40, ... 400:
# ↓---------↓---------↓---------↓---------↓---------↓---------↓
nums_d = []
for idx in range(10):
    nums_d.append(40 * idx)
# ↑---------↑---------↑---------↑---------↑---------↑---------↑

# 5. Python provides an even shorter syntax, called list comprehension.
# FIX the (hopefully obvious) computation error here.
# ↓---------↓---------↓---------↓---------↓---------↓---------↓
nums_e = [42 * idx for idx in range(11)]
# ↑---------↑---------↑---------↑---------↑---------↑---------↑

# 6. Your turn!
# Create [0, 15, 30, 45, 60, 75, 90, 105, 120, 135, 150, 165]
# ↓---------↓---------↓---------↓---------↓---------↓---------↓
nums_f = []
# ↑---------↑---------↑---------↑---------↑---------↑---------↑

# 🖐 HALT! No code editing below this line!
# ↑---------↑---------↑---------↑---------↑---------↑---------↑

nums40 = [0, 40, 80, 120, 160, 200, 240, 280, 320, 360, 400]
nums15 = [0, 15, 30, 45, 60, 75, 90, 105, 120, 135, 150, 165]
assert nums_a == nums_b, "\n  nums_b is " + str(nums_b) + "\n  expected: " + str(nums40)
assert nums_a == nums_c, "\n  nums_c is " + str(nums_c) + "\n  expected: " + str(nums40)
assert nums_a == nums_d, "\n  nums_d is " + str(nums_d) + "\n  expected: " + str(nums40)
assert nums_a == nums_e, "\n  nums_e is " + str(nums_e) + "\n  expected: " + str(nums40)
assert nums_a == nums_f, "\n  nums_f is " + str(nums_f) + "\n  expected: " + str(nums15)

print("+---------+---------+---------+---------+---------+---------+")
input("FIXED You did it!")

# ----------------------------------------------------------------------
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# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <https://www.gnu.org/licenses/>.