I'm new to programming world, and I'm struggling with recursion.
This is my code, but I'm not sure why it doesn't work :(
enter_number = input("enter 'x' value: ")
def g(x):
if x == 0:
return 1
elif x == 1:
return 2
else:
return g(x−1) + g(x−3) + g(x−4)
print(g(enter_number))
thank you
Your g function doesn't handle inputs 2 and 3.
Related
Is there a way to store the output of the function but only if it isnt false, and not having to call the function 2 times as in the example?
def example(x):
if x>=5:
return "great"
else:
return False
def main():
x = 5
if example(x):
asnwer = example(x)
else:
print("x<5")
main()
If your Python interpreter version 3.8 or greater, you can use Assignment Expresions
import random
def example():
return random.randint(0, 10)
if (result := example()) >= 5:
print(result)
else:
print("x < 5")
def main():
x = 5
result = example(x)
asnwer = result if result else print("x<5")
You could also just modify the function:
def example(x):
return "Great" if x>=5 else print("x<5")
def main():
x = 5
asnwer = example(x)
main()
This would give asnwer == None when x<5 and asnwer == Great when x>=5.
I'm learning to program with python and I came across this issue: I'm trying to make a Guessing Game, and while trying to check for the win condition, the function doesn't recognise the input variable, which I made sure I returned with a previous function. So i get the 'name << 'first_input' is not defined' >> error. I thought it had something to do with the variable not being global or sth like that.
import random
ran_int = random.randint(1,100)
guesses = 0
# here you input the number and it keeps asking unless you do so with 1 to 100
def ask():
first_input = 0
while first_input < 1 or first_input > 100:
first_input = int(input('Enter a number between 1 and 100: '))
return first_input
# this is just to increment the number of guesses stored for showing at the end # of the game
def guesses_inc():
global guesses
guesses += 1
return guesses
# here is where i get the error, as if my ask() function didn't return
# the value properly or as if I assigned it wrongly
def check_win_1():
if first_input == ran_int:
guesses_inc()
print(f'BINGO!\nYou guessed correctly after {guesses} times.')
elif (abs(ran_int - first_input) <= 10):
guesses_inc()
print('WARM!')
ask2()
elif first_input < 1 or first_input > 100:
print('Out of bounds!')
ask2()
else:
guesses_inc()
print('COLD!')
ask2()
ask()
check_win_1()
And here is the error
---------------------------------------------------------------------------
NameError Traceback (most recent call last)
<ipython-input-11-bfd5497995df> in <module>
----> 1 check_win_1()
NameError: name 'first_input' is not defined
I didn't paste the whole code because while testing it it returned the error at this stage so I didn't think the rest mattered for this particular problem. I tried making the var input global and stuff like that but i don't think I did it properly.
Your method call is not correct. You should call your functions like this
def check_win_1(first_input):
if first_input == ran_int:
guesses_inc()
print(f'BINGO!\nYou guessed correctly after {guesses} times.')
elif (abs(ran_int - first_input) <= 10):
guesses_inc()
print('WARM!')
ask2()
elif first_input < 1 or first_input > 100:
print('Out of bounds!')
ask2()
else:
guesses_inc()
print('COLD!')
ask2()
first_input = ask()
check_win_1(first_input)
The error is there because you are trying to use first_input somewhere (i.e. inside check_win_1()).
A possible, not recommended, solution is to qualify your variable as global, which should be used VERY sparingly.
Instead, it is recommended to use function parameters, so as to encapsulate your code in self-contained blocks, e.g.:
def func(a, b):
return a + b
x = func(10, 5)
rather than:
def func():
global a, b
return a + b
a = 10
b = 5
x = func()
For your that may mean doing something like:
def check_win_1(first_input, ran_int):
...
and use them accordingly, e.g.:
first_input = ask()
check_win_1(first_input, ran_int)
etc.
EDIT
Following the above principle, your code could have looked like:
import random
MIN_VAL = 1
MAX_VAL = 100
WARM_LIMIT = 10
def ask_number(
min_val=MIN_VAL,
max_val=MAX_VAL):
guess = None
while guess is None:
guess = int(input(f'Enter a number between {min_val} and {max_val}: '))
if guess < min_val or guess > max_val:
print('Out of bounds!')
guess = None
return guess
def check_guess(
guess,
target,
num_guesses,
warm_limit=WARM_LIMIT):
if guess == target:
print(f'BINGO!\nYou guessed correctly after {num_guesses} times.')
return True
else:
if (abs(guess - target) <= warm_limit):
print('WARM!')
else:
print('COLD!')
return False
# : main
target = random.randint(MIN_VAL, MAX_VAL)
num_guesses = 0
won = False
while not won:
guess = ask_number()
num_guesses += 1
won = check_guess(guess, target, num_guesses)
Can anyone explain this please?
def cube(number):
number = (number**3)
return number
def by_three(number):
if number % 3 == 0:
cube(number)
return number
else:
return False
by_three(3)
Oops, try again. by_three(3) returned 3 instead of 27
Why does this not return 27?
So the problem is that in your by_three function you are returning the parameter "number" passed into the by_three function and not returning the result of the cube function.
Your code:
def by_three(number):
if number % 3 == 0:
cube(number)
## problem is right here you should return cube(number) not number
return number
else:
return False
Fixed code.
def by_three(number):
if number % 3 == 0:
return cube(number) ## note the change here
else:
return False
Check you are not referring the returned value to variable number.The code will be like this.
def cube(number):
number = (number**3)
return number
def by_three(number):
if number % 3 == 0:
number=cube(number)
return number
else:
return False
print by_three(3)
Hope your problem is solved
For example, we have two functions:
def function1(num):
return num * 3
and second function
def function2(num):
if num%2 == 0:
print(num)
function1(num)
return num
If you call function(1), as expected it will return 1
If you call function(2), it will return 2 not 6. WHY?
Lets analyze this function2(2)
def function2(num): # num = 2
if num%2 == 0: # yes, it meets the condition
print(num)
function1(num) # it steps into function 1, this return num*3 == 6 however we do not know where it is saved (its address is unknown).
return num # this 'num' it is just the argument == 2
Hey everyone im new here and im trying to make a game called HiQ now i got the board drawn and everything and i can click on one of the pieces, but when i do the piece does change color and i get an error in the shell as well (listed below) im not sure why im getting this and i was hoping you guys could give me better insight. Ill provide my code below as well and it is coded in python 3, thank you
builtins.IndexError: list index out of range
boardcirc =[[0,0,0,1,1,1,0,0,0],
[0,0,0,1,1,1,0,0,0],
[0,0,0,1,1,1,0,0,0],
[1,1,1,1,1,1,1,1,1],
[1,1,1,1,2,1,1,1,1],
[1,1,1,1,1,1,1,1,1],
[0,0,0,1,1,1,0,0,0],
[0,0,0,1,1,1,0,0,0],
[0,0,0,1,1,1,0,0,0]]
def HiQ():
splash_screen()
make_board()
def make_board():
make_sqr()
make_circ()
get_click()
def get_click():
global count, boardcirc
while 1!=0:
count = count - 1
displaymessage("Pieces: " + str(count))
where = win.getMouse()
col = where.x//90
row = where.y//90
valid_move(row,col)
make_move(row,col)
def valid_move(row,col):
if boardcirc[row][col] == 0:
return False
if boardcirc[row-1][col] == 1 and boardcirc[row-2][col] == 1:
return True
if boardcirc[row+1][col] == 1 and boardcirc[row+2][col] == 1:
return True
if boardcirc[row][col-1] == 1 and boardcirc[row][col-2] == 1:
return True
if boardcirc[row][col+1] == 1 and boardcirc[row][col+2] == 1:
return True
def make_move(row,col):
while valid_move(row,col) == True:
col = (col*85)+42
row = (row*85)+42
circ = Circle(Point(col,row),35)
circ.setFill("white")
circ.draw(win)
thats everything that applies to the error
For your valid_move(row,col), you can't have all those if statements.
Instead of doing this, use elif's after the initial if statement, and don't forget to write an else statement
if boardcirc[row][col] == 0:
return False
if boardcirc[row-1][col] == 1 and boardcirc[row-2][col] == 1:
return True
elif boardcirc[row+1][col] == 1 and boardcirc[row+2][col] == 1:
return True
elif boardcirc[row][col-1] == 1 and boardcirc[row][col-2] == 1:
return True
elif boardcirc[row][col+1] == 1 and boardcirc[row][col+2] == 1:
return True
else:
return False
So first, the assignment given was to make the function "compute" solves it and returns the value. If the given sting is not a valid equation, returns "None"
def compute(side):
val=int(side[0])
lastop=0
for i in range(1,len(side)):
if side[i].isdigit():
if lastop=='+':
val+=int(side[i])
elif lastop=='-':
val-=int(side[i])
elif lastop=='x':
val*=int(side[i])
elif lastop=='/':
val/=int(side[i])
else:
lastop=side[i]
return val
So at this point the value would be returned. But if the function is run for ("22-11x4"), it gives 0 not 44. I've turned them into integers and why would they still give me the wrong value?
def evaluate():
val=int(side[0])
lastop=0
for i in range(1,len(side)):
if side[i].true():
print('Congrats')
elif side[i].false():
print('Try again')
And when it gets to this evaluate function, it gives the error of "invalid literal for int() with base 10: '+'" and I am not too sure what this means and how to solve.
def solve():
pass
This function "solve" I was going to get to later after I have fixed the problems in the functions before.
def main():
print("22-11x4 =", compute("22-11x4"),"(expect 44)")
print("+11x4 =", compute("+11x4"),"(expect None)")
print("22-11x4 ?= 7x5+9", evaluate("22-11x4=7x5+9"),"(expect True)")
print("solving 288/24x6=18x13x8 :", solve("288/24x6=18x13x8"))
main()
The compute function you wrote does operation by digit, also you forgot to do one, last operation after for was finished:
2 - 1 - 1 x 4 = 0
this why you got this return from the function
Here is the correct function
def compute(side):
val = 0
buf = 0
lastop = '+'
for i in range(0, len(side)):
if side[i].isdigit():
buf = buf * 10 + int(side[i])
else:
val = op(val, buf, lastop)
lastop = side[i]
buf = 0
val = op(val, buf, lastop)
return val
def op(val, buf, lastop):
if lastop == '+':
val += buf
elif lastop == '-':
val -= buf
elif lastop == 'x':
val *= buf
elif lastop == '/':
val /= buf
return val
Also in your testing string:
print("+11x4 =", compute("+11x4"),"(expect None)")
why do you expect None? it should be 44?
PS. this function could be improved yet, but I had no time to do it. anyway it works.