I am using Python Version 3.6.4
I was trying to write a basic python code in Jupyter Notebook where I found my code acting funny.
The below given code is working as expected But when I change the operation to (+) in the 4th line of code print( x, '+', y, '=', x+y) then it is resulting with Error.
Question is why is this unexpected behavior happening when there is a change of operator where multiplication works fine and addition results with error?
def fuc(x):
x = input('Enter the number:')
for y in range(1,11):
print( x, 'x', y, '=', x*y)
print(fuc(2))
The user input (i.e. x) is string. y is integer. Multiplication between string and integer is valid python operation. Addition between integer and string is not. Note that I doubt your code with multiplication works as expected, i.e. it will not multiply the number, but repeat the string, e.g.
>>> '3' * 4
'3333'
To deal with the problem you need to convert the user input to int:
x = int(input('Enter the number:'))
Note that this will not handle any invalid input, e.g. not numeric input and will raise an exception.
EDIT: Include example code snippet:
def fuc(x):
x = int(input('Enter the number:'))
for y in range(1,11):
print(x, '+', y, '=', x+y)
# print(f'{x} + {y} = {x+y}') # in 3.6+ you better use this
fuc(2)
output in python3
Enter the number:3
3 + 1 = 4
3 + 2 = 5
3 + 3 = 6
3 + 4 = 7
3 + 5 = 8
3 + 6 = 9
3 + 7 = 10
3 + 8 = 11
3 + 9 = 12
3 + 10 = 13
>>>
Normally I would use string formatting for the print, but in this case I keep as in the original code
you can try this piece of code:
def fuc(x):
x = float(input('please enter your desired number'))
for i in range(1,11):#generally i is used as an iterable
print( "{}*{} '=' ",x*i)
print(fuc())
Related
So for context, I'm working on a program that requires the Guass formula. It's used to find for example, 5 + 4 + 3 + 2 + 1, or, 8 + 7 + 6 + 5 + 4 + 3 + 2 + 1.
The formula is (n*(n + 1))/2,
I tried to incorporate this into a for loop, but I'm getting an error stating:
"'float' object cannot be interpreted as an integer"
This is my code:
# Defining Variables #
print("Give me a start")
x = int(input())
print("Give me a delta")
y = int(input())
print("Give me an amount of rows")
z = int(input())
archive_list = []
f = z + 1
stop = z*f
final_stop = stop/2
# Main Logic #
for loop in range(1,final_stop,1):
print("hi")
I would appreciate a response on why it wasn't working as well as a fixed code.
Thanks in advance!
As #ForceBru noted in his excellent comment, the problem is that the endpoint final_stop is a float, instead of an int.
The reason is because when computing it you used a single / instead of double.
If you replace
final_stop = stop/2
with
final_stop = stop//2,
then it should work fine.
Hope to find some help here with a new excercise.
I luckily understand how to use recursive functions, but this one is killing me, im probably just thinking too much outside of the box.
We're given a string:
c = "3+4*5+6+1*3"
And now we have to code a function, which recursivly gives us the result of that calculation.
Now i know the recursive end should be the length of the string, which should be 1.
Our professor did give us another example which we should use for this function.
int(number)
string.split(symbol, 1)
we have following code given:
c = "3+4*5+6+1*3"
print(c)
print()
sub1, sub2 = c.split("+", 1)
print("Result with '+':")
print("sub1=" + sub1)
print("sub2=" + sub2)
print()
sub1, sub2 = c.split("*", 1)
print("Result with '*':")
print("sub1=" + sub1)
print("sub2=" + sub2)
print()
My thoughts were to split the strings to a minimum, so i can turn them into integers and than sum them together. But im absolutly lost there how the code should look like, im a real beginner so im really sorry. I dont even know it the beginning i was thinking of is right. Still hoping, someone can help!
what i had:
def calc(string):
if len(string) == 1:
return string
Thanks for all of you!
Greets
Chrissi
I created a function that solves equations like these. However, the only characters possible are numbers, and operators add (+) and mult (*). If you try to use any other characters such as spaces, there's going to be errors.
# Solves a mathematical equation containing digits [0-9], and operators
# such as add + or multiply *
def solve(equation, operators, oindex=0):
# If an operator is available, use the operator
if (oindex < len(operators)):
# Get the current operator and pair: a op b
op = operators[oindex]
pair = equation.split(op, 1)
# If the pair is a pair (has 2 elements)
if (len(pair) == 2):
# Solve left side
a = solve(pair[0], operators)
# Solve right side
b = solve(pair[1], operators)
# If current operator is multiply: multiply a and b
if (op == '*'):
print(a, '*', b, '=', a*b)
return a * b
# If current operator is add: add a and b
elif (op == '+'):
print(a, '+', b, '=', a+b)
return a + b
# If it's not a pair, try using another operator
else:
return solve(equation, operators, oindex+1)
else:
# If no operators are available, then equation is
# just a number.
return int(equation)
if __name__ == '__main__':
equation = "3+4*5+6+1*3"
# If mult (*) takes precedence, operator order is "+*"
# > 3+4*5+6+1*3 = ((3)+((4*5)+((6)+(1*3))))
# = ((3)+((20)+((6)+(3))))
# = ((3)+(20+(9)))
# = ((3)+(29))
# = (32)
print("MULT, then ADD -> ",equation + " = ", solve(equation, "+*"))
# If add (+) takes precedence, operator order is "*+"
# > 3+4*5+6+1*3 = ((3+4)*(((5)+(6+1))*(3)))
# = ((7)*((5+7)*(3)))
# = ((7)*(12*3))
# = (7*36)
# = (252)
print("ADD, then MULT -> ",equation + " = ", solve(equation, "*+"))
To set the operators, you can use the paramter operators, which is a string that takes all supported operators. In this case: +*.
The order of these characters matter, changing the precedence of each operator inside the equation.
Here's the output:
4 * 5 = 20
1 * 3 = 3
6 + 3 = 9
20 + 9 = 29
3 + 29 = 32
MULT, then ADD -> 3+4*5+6+1*3 = 32
3 + 4 = 7
6 + 1 = 7
5 + 7 = 12
12 * 3 = 36
7 * 36 = 252
ADD, then MULT -> 3+4*5+6+1*3 = 252
import matplotlib.pyplot as plt
string = input("Please enter a function: ")
Here the code that I want to convert. I want to convert this to variable to graph the function. Other part of the code will be:
domain = [x for x in range(-10,10)]
range = [string for x in domain]
And I want the string in range be variable in order to Python can run the code. For example if a user enter, let's say,
string = "x ** 2 + x * 2 + 1"
Then I want a method or something that will convert this string to a variable. And in the end I want to get:
string = x ** 2 + x * 2 + 1
By getting this I can get a plot from matplotlib. Finally code will be:
domain = [x for x in range(-10,10)]
range = [x ** 2 + x * 2 + 1 for x in domain]
Thanks in advance!
A quick & dirty approach would be to use the native function eval. For instance define the following high-order function:
def str_to_func(string):
return lambda x: eval(string)
which can be used in this way:
function = str_to_func(string)
values = [function(x) for x in domain]
plt.plot(domain, values)
I am trying to solve a problem of multiplication. I know that Python supports very large numbers and it can be done but what I want to do is
Enter 2 numbers as strings.
Multiply those two numbers in the same manner as we used to do in school.
Basic idea is to convert the code given in the link below to Python code but I am not very good at C++/Java. What I want to do is to understand the code given in the link below and apply it for Python.
https://www.geeksforgeeks.org/multiply-large-numbers-represented-as-strings/
I am stuck at the addition point.
I want to do it it like in the image given below
So I have made a list which stores the values of ith digit of first number to jth digit of second. Please help me to solve the addition part.
def mul(upper_no,lower_no):
upper_len=len(upper_no)
lower_len=len(lower_no)
list_to_add=[] #saves numbers in queue to add in the end
for lower_digit in range(lower_len-1,-1,-1):
q='' #A queue to store step by step multiplication of numbers
carry=0
for upper_digit in range(upper_len-1,-1,-1):
num2=int(lower_no[lower_digit])
num1=int(upper_no[upper_digit])
print(num2,num1)
x=(num2*num1)+carry
if upper_digit==0:
q=str(x)+q
else:
if x>9:
q=str(x%10)+q
carry=x//10
else:
q=str(x%10)+q
carry=0
num=x%10
print(q)
list_to_add.append(int(''.join(q)))
print(list_to_add)
mul('234','567')
I have [1638,1404,1170] as a result for the function call mul('234','567') I am supposed to add these numbers but stuck because these numbers have to be shifted for each list. for example 1638 is supposed to be added as 16380 + 1404 with 6 aligning with 4, 3 with 0 and 8 with 4 and so on. Like:
1638
1404x
1170xx
--------
132678
--------
I think this might help. I've added a place variable to keep track of what power of 10 each intermediate value should be multiplied by, and used the itertools.accumulate function to produce the intermediate accumulated sums that doing so produces (and you want to show).
Note I have also reformatted your code so it closely follows PEP 8 - Style Guide for Python Code in an effort to make it more readable.
from itertools import accumulate
import operator
def mul(upper_no, lower_no):
upper_len = len(upper_no)
lower_len = len(lower_no)
list_to_add = [] # Saves numbers in queue to add in the end
place = 0
for lower_digit in range(lower_len-1, -1, -1):
q = '' # A queue to store step by step multiplication of numbers
carry = 0
for upper_digit in range(upper_len-1, -1, -1):
num2 = int(lower_no[lower_digit])
num1 = int(upper_no[upper_digit])
print(num2, num1)
x = (num2*num1) + carry
if upper_digit == 0:
q = str(x) + q
else:
if x>9:
q = str(x%10) + q
carry = x//10
else:
q = str(x%10) + q
carry = 0
num = x%10
print(q)
list_to_add.append(int(''.join(q)) * (10**place))
place += 1
print(list_to_add)
print(list(accumulate(list_to_add, operator.add)))
mul('234', '567')
Output:
7 4
7 3
7 2
1638
6 4
6 3
6 2
1404
5 4
5 3
5 2
1170
[1638, 14040, 117000]
[1638, 15678, 132678]
I've been asked to do the following:
Using a while loop, you will write a program which will produce the following mathematical sequence:
1 * 9 + 2 = 11(you will compute this number)
12 * 9 + 3 = 111
123 * 9 + 4 = 1111
Then your program should run as far as the results contain only "1"s. You can build your numbers as string, then convert to ints before calculation. Then you can convert the result back to a string to see if it contains all "1"s.
Sample Output:
1 * 9 + 2 = 11
12 * 9 + 3 = 111
123 * 9 + 4 = 1111
1234 * 9 + 5 = 11111
Here is my code:
def main():
Current = 1
Next = 2
Addition = 2
output = funcCalculation(Current, Addition)
while (verifyAllOnes(output) == True):
print(output)
#string concat to get new current number
Current = int(str(Current) + str(Next))
Addition += 1
Next += 1
output = funcCalculation(Current, Next)
def funcCalculation(a,b):
return (a * 9 + b)
def verifyAllOnes(val):
Num_str = str(val)
for ch in Num_str:
if(str(ch)!= "1"):
return False
return True
main()
The bug is that the formula isn't printing next to the series of ones on each line. What am I doing wrong?
Pseudo-code:
a = 1
b = 2
result = a * 9 + b
while string representation of result contains only 1s:
a = concat a with the old value of b, as a number
b = b + 1
result = a * 9 + b
This can be literally converted into Python code.
Testing all ones
Well, for starters, here is one easy way to check that the value is all ones:
def only_ones(n):
n_str = str(n)
return set(n_str) == set(['1'])
You could do something more "mathy", but I'm not sure that it would be any faster. It would much more easily
generalize to other bases (than 10) if that's something you were interested in though
def only_ones(n):
return (n % 10 == 1) and (n == 1 or only_ones2(n / 10))
Uncertainty about how to generate the specific recurrence relation...
As for actually solving the problem though, it's actually not clear what the sequence should be.
What comes next?
123456
1234567
12345678
123456789
?
Is it 1234567890? Or 12345678910? Or 1234567900?
Without answering this, it's not possible to solve the problem in any general way (unless in fact the 111..s
terminate before you get to this issue).
I'm going to go with the most mathematically appealing assumption, which is that the value in question is the
sum of all the 11111... values before it (note that 12 = 11 + 1, 123 = 111 + 11 + 1, 1234 = 1111 + 111 + 11 + 1, etc...).
A solution
In this case, you could do something along these lines:
def sequence_gen():
a = 1
b = 1
i = 2
while only_ones(b):
yield b
b = a*9 + i
a += b
i += 1
Notice that I've put this in a generator in order to make it easier to only grab as many results from this
sequence as you actually want. It's entirely possible that this is an infinite sequence, so actually running
the while code by itself might take a while ;-)
s = sequence_gen()
s.next() #=> 1
s.next() #=> 11
A generator gives you a lot of flexibility for things like this. For instance, you could grab the first 10 values of the sequence using the itertools.islice
function:
import itertools as it
s = sequence_gen()
xs = [x for x in it.islice(s, 10)]
print xs