better organization.

Author: RobisonTorres

Challenges/BasicChallenges_7kyu/README.md

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+This repository contains my personal solution to the
+7_kyu's most popular challenges of the site codewars.

Challenges/BasicChallenges_7kyu/add_binary.py

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+print('From Code Wars')
+print()
+
+def add_binary(a, b):
+
+    # This function sums two numbers (a, b),\
+    # and return the result in binary as str.
+    return f'{bin(a + b)[2:]}'
+    # Bin converts decimal to binary.
+    # return format(a + b, 'b') - clever.
+
+print(add_binary(1, 1))  # Outputs - 10
+print(add_binary(5, 9))  # Outputs - 1110

Challenges/BasicChallenges_7kyu/arithmetic.py

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+print('From Code Wars')
+print()
+
+def arithmetic(a, b, operator):
+
+    # A simple calculator.
+    if operator == 'add':
+        return a + b
+    elif operator == 'subtract':
+        return a - b
+    elif operator == 'multiply':
+        return a * b
+    elif operator == 'divide':
+        return a / b
+
+print(arithmetic(5, 2, 'add'))  # Outputs - 7
+print(arithmetic(5, 2, 'subtract'))  # Outputs - 3

Challenges/BasicChallenges_7kyu/calculate_years.py

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+print('From Code Wars')
+print()
+
+def calculate_years(principal, interest, tax, desired):
+
+    # This function calculates how many years\
+    # is necessary to reach a desired amount of money.
+    year = 0
+    while principal < desired:
+        principal += principal * interest - principal * interest * tax
+        year += 1
+    return year
+
+print(calculate_years(1000, 0.05, 0.18, 1100))
+# Outputs - 3 years. It means,\ starting with a principal\
+# of 1000 it will take 3 years to reach a desired amount of 1100.

Challenges/BasicChallenges_7kyu/capitalize.py

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+print('From Code Wars')
+print()
+
+def capitalize(s):
+
+    # Given a string, capitalize the letters that occupy even indexes\
+    # and odd indexes separately. Ex: ['AbCdEf', 'aBcDeF']
+    a = ''.join([l.upper() if n % 2 else l for n, l in enumerate(s)])
+    return [a, a.swapcase()]
+
+print(capitalize('abracadabra'))  # Outputs - ['AbRaCaDaBrA', 'aBrAcAdAbRa']

Challenges/BasicChallenges_7kyu/capitals.py

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+print('From Code Wars.')
+print()
+
+def capitals(word):
+
+    # This function takes a word and return all\
+    # indexes of capitalized letters.
+    return [a[0] for a in enumerate(word) if a[1].isupper()]
+
+print(capitals('CodEWaRs'))  # Outputs - [0, 3, 4, 6]

Challenges/BasicChallenges_7kyu/check_coupon.py

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+from datetime import datetime
+print('From Code Wars.')
+print()
+
+def check_coupon(entered_code, correct_code, current_date, expiration_date):
+
+    # This function checks if a coupon is valid or not.
+    return entered_code is correct_code \
+           and datetime.strptime(current_date, "%B %d, %Y") \
+           <= datetime.strptime(expiration_date, "%B %d, %Y")
+
+print(check_coupon('123', '123', 'September 5, 2014', 'October 1, 2014'))
+# Outputs - True
+print(check_coupon('123a', '123', 'September 5, 2014', 'October 1, 2014'))
+# Outputs - False

Challenges/BasicChallenges_7kyu/check_exam.py

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+print('From Code Wars.')
+print()
+
+def check_exam(arr1, arr2):
+
+    # This function checks an exam (arr1) with the student's answers (arr2),
+    # and return the total points or 0 if the total is negative.
+    return max(0, sum([0 if y == '' else 4 if x == y \
+        else - 1 for x, y in zip(arr1, arr2)]))
+
+print(check_exam(['a', 'a', 'c', 'b'], ['a', 'a', 'b',  '']))  # Outputs - 7

Challenges/BasicChallenges_7kyu/count_sheep.py

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+print('If you can\'t sleep, just count sheep!!')
+print()
+
+def count_sheep(n):
+
+    # This function will count the amount of sheep based in any given number.
+    return ''.join([str(number) + ' sheep...' for number in range(1, n+1)])
+
+print(count_sheep(3))  # Outputs - 1 sheep...2 sheep...3 sheep...

Challenges/BasicChallenges_7kyu/declare_winner.py

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+print('From Code Wars')
+print()
+
+class Fighter(object):
+    def __init__(self, name, health, damage_per_attack):
+        self.name = name
+        self.health = health
+        self.damage_per_attack = damage_per_attack
+
+    def __str__(self): return "Fighter({}, {}, {})"\
+        .format(self.name, self.health, self.damage_per_attack)
+    __repr__ = __str__
+
+def declare_winner(fighter1, fighter2, first_attacker):
+    cur, opp = (fighter1, fighter2) if first_attacker == fighter1.name \
+        else (fighter2, fighter1)
+    while cur.health > 0:
+        opp.health -= cur.damage_per_attack
+        cur, opp = opp, cur
+    return opp.name
+
+print(declare_winner(Fighter("Lew", 10, 2), Fighter("Harry", 5, 4), "Lew"))