CODEWITHSUNDEEP
pythonfloating-point
orange
orange

Reputation: 5395

Floating Point in Python

I'm learning via Learn Python The Hard Way and I've come across:

Notice the math seems “wrong”? There are no fractions, only whole numbers. Find out why by researching what a “floating point” number is.

I've read what it is on: http://docs.python.org/tutorial/floatingpoint.html

I can't figure out on how I can output floating point numbers, I've thought about using round(3 + 3, 2).

Is this right?

Upvotes: 9

Views: 52188

Answers (7)

Channing Grayned
Channing Grayned

Reputation: 1

python console print(3 + 2 + 1 - 5 + 4 % 2 - 1 / 4 + 6) I get 7 but in pycharm I get 6.75.

Upvotes: 0

Aniruddha Rairikar
Aniruddha Rairikar

Reputation: 1

Any number with a decimal is a floating point number.

In python take the following example,

If you divide 11/4 the output will be 2 [here 11 is not a floating point number]

But if you divide 11.0/4, the output will be 2.75 [here 11.0 is a floating point number].

Here's a screenshot

Upvotes: 0

Pablo
Pablo

Reputation: 285

For floating point numbers you write a period after the number, and a zero (if it's a whole number).

Like this:

1.0 <---- Floating point.

1 <------- integer

That is how python interprets them.

if my_answer != your_question:
    print "I did not understand your question. Please rephrase it."
else:
    print "Good luck. Python is fun."

I agree with rohit, the 0 is not needed. Although it makes things easier for beginners.

Upvotes: 8

abe
abe

Reputation: 11

Orange, read the last question in the lesson, the author gave you the answer

Why does / (divide) round down? It's not really rounding down; it's just dropping the fractional part after the decimal. Try doing 7.0 / 4.0 and compare it to 7 / 4 and you'll see the difference.

good luck

Upvotes: 1

user225312
user225312

Reputation: 131567

3 is an integer.

3.0 is a float. 

>>> type(3)
<type 'int'>
>>> type(3.0)
<type 'float'>

round():

Round a number to a given precision in decimal digits (default 0 digits). This always returns a floating point number.

So that is why in your case, 6.0 is returned.

Upvotes: 2

Rohit
Rohit

Reputation: 7629

Agree with all of the answers above. You don't even need to put a zero after the period though.

For example:

In [1]: type(3)
Out[1]: <type 'int'>

In [2]: type(3.)
Out[2]: <type 'float'>

Upvotes: 1

Ignacio Vazquez-Abrams
Ignacio Vazquez-Abrams

Reputation: 798456

Passing a value to the float() constructor will make it a float if possible.

print float(2)
print float('4.5')

Use string interpolation or formatting to display them.

print '%.3f' % 4.53

Upvotes: 5

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