Python: Using Variable From Different Function Without Renaming - python-3.x

Question

I'm working on creating a short battle from a game (for fun). I have several variables that need to change throughout the sequence, such as m_hp (monster health). Here is the code I have (Forgive me if I formatted incorrectly, this is my first time using this website):
def battle(p_lvl):
print("A goblin engages you in battle!")
p_hp = p_lvl * 25 + 25
p_dmg = p_lvl * 7 + 5
print("Player Stats (Level: " + str(p_lvl) + " Health: " + str(p_hp) + " ATK: " + str(p_dmg) + ")")
m_lvl = p_lvl - 1
m_hp = m_lvl * 20 + 15
m_dmg = m_lvl * 6 + 3
scr_dmg = m_hp / 4
dus_eft = p_hp / 5
print("Goblin Stats (Level: " + str(m_lvl) + " Health: " + str(m_hp) + " ATK: " + str(m_dmg) + ")")
act()
def act():
menu = 'Attack','Block','Use Item'
print("What will you do?")
print(menu)
action = input()
if action == ‘Attack':
m_hp = m_hp - p_dmg
print("You dealt " + str(p_dmg) + "damage to the goblin!")
p_hp = p_hp - m_dmg
print("The goblin struck back with " + str(m_dmg) + " damage!”)
act()
I get problems after act() initiates. If I enter "attack" for the input(), I get this error:
UnboundLocalError: local variable 'm_hp' referenced before assignment
To my understanding, this is because I have m_hp placed under battle(), but act() cannot reach it. I want to be able to change m_hp without writing it in act(). I believe if I do so, then m_hp will reset each time act() initiates, and m_hp cannot drop. I've searched through questions on here, but the cases I've seen don't seem to work. Also, I am admittedly new to coding, so I couldn't understand some of the solutions.
Tl;dr I'm looking for a simple solution as to how to use variables from a different function without putting them into the function.

Answer 1

You're seeing that error message because the 'm_hp' variable is local to the scope of the 'battle' function. It is created inside the function, and ceases to exist after that function exits.
It doesn't look like battle actually gets called anywhere though...
It also looks like you call the act() function before you define it.
There are a number of other reasons why the code would not run if that error was fixed as well.
The feature you're probably looking for where you have access to variables inside multiple functions without passing them in is some kind of global variable. In general, global variables are strongly discouraged anywhere they can be reasonably avoided.
I've retooled your code a bit so that you have something working to mess around with. I've used classes to try to group related things together.
There is now a 'Player' object with all the player's stats and a 'Monster' object with all the monster's stats.
Try running the code below, then making incremental changes and seeing if it continues to run.
class Player(object):
def __init__(self, level):
self.level = level
self.stats_for_level()
def stats_for_level(self):
self.attack_damage = (self.level * 7) + 5
self.hitpoints = (self.level * 25) + 25
def take_damage(self, damage):
self.hitpoints -= damage
def print_stats(self):
print("Player Stats (Level: " + str(self.level) +
" Health: " + str(self.hitpoints) +
" ATK: " + str(self.hitpoints) + ")")
class Monster(object):
def __init__(self, level, name="Goblin"):
self.level = level
self.name = name
self.stats_for_level()
def stats_for_level(self):
self.attack_damage = (self.level * 6) + 3
self.hitpoints = (self.level * 20) + 15
def take_damage(self, damage):
self.hitpoints -= damage
def print_stats(self):
print(self.name + " Stats (Level: " + str(self.level) +
" Health: " + str(self.hitpoints) +
" ATK: " + str(self.hitpoints) + ")")
class Game(object):
def __init__(self, starting_level=1):
self.player = Player(starting_level)
# create monster
self.monster = Monster(level=self.player.level - 1, name='Goblin')
def battle(self, player, monster):
print("A {} engages you in battle!".format(monster.name))
monster.take_damage(player.attack_damage)
print("You dealt " + str(player.attack_damage) + " damage to the goblin!")
self.player.take_damage(monster.attack_damage)
print("The goblin struck back with " + str(monster.attack_damage) + " damage!")
def act(self):
# print stats
self.player.print_stats()
self.monster.print_stats()
# show menu
menu = 'Attack', 'Block', 'Use Item'
print(menu)
print("\nWhat will you do?: ")
action = input()
# take an action
if action == 'Attack':
self.battle(self.player, self.monster)
def main():
game = Game(starting_level=3)
while(True):
game.act()
if __name__ == '__main__':
main()