This question already has answers here:
Print Combining Strings and Numbers
(6 answers)
Closed 2 years ago.
I'm a very beginner and know only the very basic syntax. I am trying to make a circumference calculator, with the user inputting the radius. This is what I have right now, but I want to be able to have a text answer like "The circumference of this circle is ____". Right now I can only output the answer.
rad = input("Enter the radius of circle: ")
radius = float(rad)
circumference = 2 * 3.14 * radius
print(circumference)
Python 3
Use f-string to format result:
rad = input("Enter the radius of circle: ")
radius = float(rad)
circumference = 2 * 3.14 * radius
print(f'The circumference of this circle is {circumference}')
Python 2
Format string:
rad = input("Enter the radius of circle: ")
radius = float(rad)
circumference = 2 * 3.14 * radius
print('The circumference of this circle is {0}'.format(circumference))
Another Option: Concatenating String Directly
Less elegant, yet still works:
rad = input("Enter the radius of circle: ")
radius = float(rad)
circumference = 2 * 3.14 * radius
print('The circumference of this circle is ' + str(circumference))
You can use
print(f"The circumference of this circle is {circumference}")
But also you do not want to use 3.14 for pi. You can do
import math
and then use math.pi for a more accurate number.
Related
The volume and surface area of a sphere can be calculated with the following formulas. Create this as a terminal application. Write one function for volume and another function for surface area. The results should display both the volume and the surface area rounded to 2 decimal places. Use pi from Python’s math module. Include the following doctests. You must get pass
all tests to receive full credit. Pay close attention to how you name your functions. They must
match
volume examples/doctests:
round(volume_of_sphere(0), 2)
0.0
round(volume_of_sphere(1), 2)
4.19
round(volume_of_sphere(12.3), 2)
7794.78
round(volume_of_sphere(18.9), 2)
28279.65
round(volume_of_sphere(33.33), 2)
155093.84
surface area examples/doctests:
round(surface_area(0), 2)
0.0
round(surface_area(1), 2)
12.57
round(surface_area(12.3), 2)
1901.17
round(surface_area(18.9), 2)
13959.84
round(surface_area(33.33), 2)
155093.84
MY CODE:
''' Python3 program to calculate Volume and
Surface area of Sphere'''
# Importing Math library for value Of PI
import math
pi = math.pi
# Function to calculate Volume of Sphere
def volume(r):
vol = (4 / 3) * pi * r * r * r
return vol
# Function To Calculate Surface Area of Sphere
def surfacearea(s):
sur_ar = 4 * pi * r * r
return sur_ar
# Driver Code
radius = round(volume(1), 2)
area = round(area(0), 2)
print( "Volume Of Sphere : ", volume(radius) )
print( "Surface Area Of Sphere : ", surfacearea(area) )
The two programs below will find the surface area and the volume of a sphere with the radius. This is just a simpler way. The first program is more accurate but both will do the job.
pi=22/7
radian = float(input('Radius of sphere: '))
sur_area = 4 * pi * radian **2
volume = (4/3) * (pi * radian ** 3)
print("Surface Area is: ", sur_area)
print("Volume is: ", volume)
or
PI = 3.14
radius = float(input('Please Enter the Radius of a Sphere: '))
sa = 4 * PI * radius * radius
Volume = (4 / 3) * PI * radius * radius * radius
print("\n The Surface area of a Sphere = %.2f" %sa)
print("\n The Volume of a Sphere = %.2f" %Volume)
Since there is no obvious question here, I am assuming the objective is to complete the mathematical functions and pass the doctests. Having said that, it would be quite impossible to do that without being mathematically incorrect because the last two doctests for the surface area function are wrong, round(surface_area(18.9), 2) should be 4488.83 not 13959.84 and round(surface_area(33.33), 2) should be 13934.72 and not 155093.84.
I'm trying to print out the x,y value for a line with a certain degree which intersects a circle with a specified radius.
Lets say for example that the line is pointing straight up at 90 degrees.
import math
degree = 90
radius = 10
x = radius * math.cos(degree)
y = radius * math.sin(degree)
print(x,y)
This prints out -4.480736161291701 8.939966636005579 but according to my calculator is supposed to print 0 10 on deg.
I have already tried adding math.radians and math.degrees before the degree var in the x = and y =, but it doesn't come out correctly any time I've tried. The link I found to the point where a line with degree intersects a circle is here, the sin/cos values are flipped 'tho for the x and y value in the solution.
Simply said, how would I make the 90 be in degrees instead of radians to get the correct x,y?
EDIT:
by adding math.radians:
x = radius * math.cos(math.radians(degree))
y = radius * math.sin(math.radians(degree))
it returned 6.123233995736766e-16 10.0
~~~
by adding math.degrees:
x = radius * math.cos(math.degrees(degree))
y = radius * math.sin(math.degrees(degree))
it returned -2.995153947555356 -9.540914674728182
In Python, you can use math.radians to convert from degrees to radians. Note that it is not just Python that defaults to radians, it is usually the standard in mathematics to talk about angles in radians.
Although, in general, you can always use the conversion formula
radians = pi * degrees / 180
You can use math.radians(degree) to convert to radians. All python's default trig functions work in radians. So your code becomes:
import math
degree = 90
radius = 10
x = radius * math.cos(math.radians(degree))
y = radius * math.sin(math.radians(degree))
print(x,y)
And this produces the correct result: 6.123233995736766e-16 10.0, with some odd floating point behavior you can fix with appropriate rounding.
All angles in most of the math libraries are in radians. The input to math.cos should be radians but you are passing in degrees.
import math
degree = 90
radius = 10
x = radius * math.cos(math.radians(degree))
y = radius * math.sin(math.radians(degree))
print x,y
>0, 10
math.radians is nothing more than doing (pi * degree / 180 )
If you're writing a somewhat longer code, you can make your code work in degrees by putting in the following lines in the beginning:
from math import sin, cos, tan, asin, acos, atan
def s(x):
return sin(rad(x))
def c(x):
return cos(rad(x))
def t(x):
return tan(rad(x))
def sa(x):
return deg(asin(x))
def ca(x):
return deg(acos(x))
def ta(x):
return deg(atan(x))
Then, throughout your code, instead of typing sin(90) you would type s(90), or for arcsin(90) you would type sa(90). (I couldn't make the code word as for arcsine, since as is already a Python word)
Now, you would just type up your code as though it were in degrees and everything should work out fine.
I am trying to solve a homework: I am required to write a program which will calculate the length of a ladder based on two inputs, that is the desired height to be reached and the angle created by leaning the ladder toward the wall.
I used the following formula to convert degrees to radians :
radians = (math.pi / 180) * x # x is the given angle by the user.
I imported the math library as well to use its functions.
def main():
import math
print("this program calculates the length of a ladder after you give the height and the angle")
h = eval(input("enter the height you want to reach using the ladder"))
x = eval(input("enter the angle which will be created be leaning the ladder to the wall"))
radians = ( math.pi / 180 ) * x
length = h / math.sin(x)
print("the length is:", length)
main()
What exactly am I doing wrong?
I know the code is missing something and would appreciate it if someone could help me fill the gap.
You never used radians after you calculate it.
i.e. length = h / math.sin(radians)
To make crickt_007's right answer absolutely clear: radians which you did not use after you calculate it should be the argument of the sine:
length = h / math.sin(radians)
you calculate radians,thats ok,but problem is you never used that radians value. i think your code must be changed as follows :)
def main():
import math
print("this program calculates the length of a ladder after you give the height and the angle")
h = eval(input("enter the height you want to reach using the ladder"))
x = eval(input("enter the angle which will be created be leaning the ladder to the wall"))
radians = ( math.pi / 180 ) * x
length = h / math.sin(radians)
print("the length is:", length)
main()
if your both input will be 5,output is the length is: 57.36856622834928
I'm trying to make this program in Python which asks for the surface area and volume of a cylinder. At the end, it asks the user if it wants to calculate volume/surface area. However, if they do type in Yes, nothing happens. What is wrong with my code?
Secondly, I tries using math.pi but it didn't work, what should I do.
The code is long so only scroll down to the important parts:
print("Welcome to the volume and surface area cylinder calculator powered by Python!")
response = input("To calculate the volume type in 'vol', to calculate the surface area, type in 'SA': ")
if response=="vol" or response =="SA":
pass
else:
print("Please enter a correct statement.")
response = input("To calculate the volume type in 'vol', to calculate the surface area, type in 'SA': ")
if response=="vol":
#Below splits
radius, height = [float(part) for part in input("What is the radius and height of the cylinder? (e.g. 32, 15): ").split(',')]
PI = 3.141592653589793238462643383279502884197169399375105820974944592307816406286
volume = PI*radius*radius*height
decimal_places = int(input("How many decimal places do you want it to?: "))
print("The volume of the cylinder is {0:.{1}f}cm\u00b3".format(volume, decimal_places))
verify = input("Do you want to find out the surface area (type in Yes or No): ")
verify = verify.capitalize
if verify == "Yes":
radius, height = [float(part) for part in input("What is the radius and height of the cylinder? (e.g. 32, 15): ").split(',')]
PI = 3.141592653589793238462643383279502884197169399375105820974944592307816406286
SA = int(2)*PI*radius*radius+int(2)+radius*radius*height
decimal_places = int(input("How many decimal places do you want it to?: "))
print("The surface area of the cylinder is {0:.{1}f}cm\u00b2".format(SA, decimal_places))
if verify == "No":
pass
if response =="SA":
#Below splits
radius, height = [float(part) for part in input("What is the radius and height of the cylinder? (e.g. 32, 15): ").split(',')]
PI = 3.141592653589793238462643383279502884197169399375105820974944592307816406286
SA = int(2)*PI*radius*radius+int(2)+radius*radius*height
decimal_places = int(input("How many decimal places do you want it to?: "))
print("The surface area of the cylinder is {0:.{1}f}cm\u00b2".format(SA, decimal_places))
verify = input("Do you want to find out the volume (type in Yes or No): ")
verify = verify.capitalize
if verify == "Yes":
radius, height = [float(part) for part in input("What is the radius and height of the cylinder? (e.g. 32, 15): ").split(',')]
PI = 3.141592653589793238462643383279502884197169399375105820974944592307816406286
volume = PI*radius*radius*height
decimal_places = int(input("How many decimal places do you want it to?: "))
print("The volume of the cylinder is {0:.{1}f}cm\u00b3".format(volume, decimal_places))
if verify == "No":
pass
You replaced verify with a method:
verify = verify.capitalize
This'll never match either 'Yes' or 'No' because it is no longer a string. Call the method instead:
verify = verify.capitalize()
Note that your test for "No" can just be dropped, there is little point in testing for a string then just passing.
Using math.pi instead of PI otherwise works just fine:
>>> import math
>>> math.pi
3.141592653589793
>>> radius, height = 32, 15
>>> 2 * math.pi * radius ** 2 + 2 * math.pi * radius * height
9449.910701998098
>>> math.pi * radius ** 2 * height
48254.86315913922
This is my tweaked version. It avoids a lot of repetition.
from math import pi
print("Welcome to the volume and surface area cylinder calculator powered by Python!")
response = raw_input("To calculate the volume type in 'vol', to calculate the surface area, type in 'SA': ").lower()
while response not in ["vol", "sa"]:
print("Please enter a correct statement.")
response = raw_input("To calculate the volume type in 'vol', to calculate the surface area, type in 'SA': ").lower()
radius, height = [float(part) for part in raw_input("What is the radius and height of the cylinder? (e.g. 32, 15): ").split(',')]
r2 = radius ** 2
SA = 2 * pi * r2 + 2 + pi * radius * height
volume = pi * r2 * height
decimal_places = int(raw_input("How many decimal places do you want it to?: "))
if response=="vol":
print("The volume of the cylinder is {0:.{1}f}cm\u00b3".format(volume, decimal_places))
verify = raw_input("Do you want to find out the surface area (type in Yes or No): ")
if verify.lower() == "yes":
print("The surface area of the cylinder is {0:.{1}f}cm\u00b2".format(SA, decimal_places))
if response =="sa":
print("The surface area of the cylinder is {0:.{1}f}cm\u00b2".format(SA, decimal_places))
verify = raw_input("Do you want to find out the volume (type in Yes or No): ")
if verify.lower() == "yes":
print("The volume of the cylinder is {0:.{1}f}cm\u00b3".format(volume, decimal_places))
You are given the diameter across, and the length of the segment or chord. The diameter for my question is 12, and the chord is 10. You have to find the height of the shaded segment, and then print the area. The original formula is A=2/3ch + h^3/2c. My classmates got 18 for the area, but when I use my code I get 41.
This is the closest picture representation I can find. However there is a dashed line from ϴ to s.
from math import sqrt
diamStr=input("Enter the length of the diameter: ")
diameter=int(diamStr)
chordStr = input( " Enter the chord length: ")
chord = int(chordStr)
radius = (diameter/2)
s = sqrt (diameter**2+chord**2)
h = (s/2-radius)
i= (2/3*chord*h)
j=(h**3/2*chord)
area = (i+j)
print (area)
Unfortunately there's something wrong with your formula but if look at the problem with some elementary mathematics you may notice that the angle ϴ can be found using the cosine rule since we know the 3 lengths (the two radius and chord length)
In Python it would be:
theta = math.acos((radius**2 + radius**2 - chord**2)/(2*radius**2))
Since the variable theta is already in radians we can use this formula to calculate the area of the segment :
which in python would be area = 1/2 * (theta - math.sin(theta)) * radius**2
Therefore after merging all of these we come up with a elegant solution:
import math
diamStr=input("Enter the length of the diameter: ")
diameter=int(diamStr)
chordStr = input( " Enter the chord length: ")
chord = int(chordStr)
radius = (diameter/2)
theta = math.acos((radius**2 + radius**2 - chord**2)/(2*radius**2))
area = 1/2 * (theta - math.sin(theta)) * radius**2
#print(round((area),2))
print(area)
If you enter diameter as 12cm and chord length as 10 you'll get 18.880864248381847 but you can round it to any number of decimal places you want by the round() function.
eg: print(round((area),2)) prints 18.88