Hướng dẫn ceil decimal python

You want to round your answer.

Nội dung chính

• Python float precision truncate
• Python float precision ceil
• Python float precision floor
• Python decimal format
• Python round numbers
• Limiting floats to two decimal points

round[value,significantDigit] is the ordinary solution to do this, however this sometimes does not operate as one would expect from a math perspective when the digit immediately inferior [to the left of] the digit you're rounding to has a 5.

Here's some examples of this unpredictable behavior:

>>> round[1.0005,3]
1.0
>>> round[2.0005,3]
2.001
>>> round[3.0005,3]
3.001
>>> round[4.0005,3]
4.0
>>> round[1.005,2]
1.0
>>> round[5.005,2]
5.0
>>> round[6.005,2]
6.0
>>> round[7.005,2]
7.0
>>> round[3.005,2]
3.0
>>> round[8.005,2]
8.01

Assuming your intent is to do the traditional rounding for statistics in the sciences, this is a handy wrapper to get the round function working as expected needing to import extra stuff like Decimal.

>>> round[0.075,2]

0.07

>>> round[0.075+10**[-2*6],2]

0.08

Aha! So based on this we can make a function...

def roundTraditional[val,digits]:
   return round[val+10**[-len[str[val]]-1], digits]

Basically this adds a really small value to the string to force it to round up properly on the unpredictable instances where it doesn't ordinarily with the round function when you expect it to. A convenient value to add is 1e-X where X is the length of the number string you're trying to use round on plus 1.

The approach of using 10**[-len[val]-1] was deliberate, as it the largest small number you can add to force the shift, while also ensuring that the value you add never changes the rounding even if the decimal . is missing. I could use just 10**[-len[val]] with a condiditional if [val>1] to subtract 1 more... but it's simpler to just always subtract the 1 as that won't change much the applicable range of decimal numbers this workaround can properly handle. This approach will fail if your values reaches the limits of the type, this will fail, but for nearly the entire range of valid decimal values it should work.

So the finished code will be something like:

def main[]:
    printC[formeln[typeHere[]]]

def roundTraditional[val,digits]:
    return round[val+10**[-len[str[val]]-1]]

def typeHere[]:
    global Fahrenheit
    try:
        Fahrenheit = int[raw_input["Hi! Enter Fahrenheit value, and get it in Celsius!\n"]]
    except ValueError:
        print "\nYour insertion was not a digit!"
        print "We've put your Fahrenheit value to 50!"
        Fahrenheit = 50
    return Fahrenheit

def formeln[c]:
    Celsius = [Fahrenheit - 32.00] * 5.00/9.00
    return Celsius

def printC[answer]:
    answer = str[roundTraditional[answer,2]]
    print "\nYour Celsius value is " + answer + " C.\n"

main[]

...should give you the results you expect.

You can also use the decimal library to accomplish this, but the wrapper I propose is simpler and may be preferred in some cases.

Edit: Thanks Blckknght for pointing out that the 5 fringe case occurs only for certain values here.

In this Python tutorial, we will discuss on how to print 2 decimal places in Python.

• Python print 2 decimal places
• Python float precision truncate
• Python float precision ceil
• Python float precision floor
• Python decimal format
• Python round numbers
• Limiting floats to two decimal points

In Python, to print 2 decimal places we will use str.format[] with “{:.2f}” as string and float as a number. Call print and it will print the float with 2 decimal places.

Example:

float = 2.154327
format_float = "{:.2f}".format[float]
print[format_float]

After writing the above code [python print 2 decimal places], Ones you will print “ format_float ” then the output will appear as a “ 2.15 ”. Here, it will format the float with 2 decimal places.

You can refer to the below screenshot python print 2 decimal places.

Python print 2 decimal places

Python float precision truncate

Firstly, we need to import math module. Then the trunc[] function is used to remove all decimal parts from the floating-point numbers and it returns only the integer part of the number.

Example:

import math
float = 12.16785
print["The value of number is: ",end=""]
print [math.trunc[float]]

After writing the above code [python float precision truncate], Ones you will print “ math.trunc[float]” then the output will appear as a “ The value of a number is: 12 ”. Here, trunc[] will print integer value after truncating.

You can refer to the below screenshot for python float precision truncate

Python Float Precision truncate

Python float precision ceil

In Python, the ceil[] function is used to return the ceiling value of a number. The ceil value is the smallest integer greater than the number.

Example:

import math
float = 12.16785
print["The smallest integer greater than number is: ",end=""]
print [math.ceil[float]]

After writing the above code [python float precision ceil], Ones you will print “ math.ceil[float] ” then the output will appear as a “ The smallest integer greater than a number is: 13 ”. Here, we used ceil to print numbers after the ceiling. It will return the smallest integer greater than the given number.

You can refer to the below screenshot for python float precision ceil.

Python Float Precision ceil

Python float precision floor

Python floor[] function is used to return the floor value of a number. The floor value is the greatest integer smaller than the number.

Example:

import math
float = 12.16785
print["The greatest integer smaller than number is: ",end=""]
print [math.floor[float]]

After writing the above code [python float precision floor], Ones you will print “math.floor[float]” then the output will appear as a “ The greatest integer smaller than a number is: 12 ”. Here, we used the floor to print numbers after flooring. It will return the greatest integer smaller than the number.

You can refer to the below screenshot for python float precision floor.

Python Float Precision floor

Python decimal format

To format decimals, we will use str.format[number] where a string is ‘{0:.3g}’ and it will format string with a number. Also, it will display the number with 1 number before the decimal and up to 2 numbers after the decimal.

Example:

number = 1.345
f = '{0:.3g}'.format[number]
print[f]

After writing the above code [python decimal format], Ones you will print “ f ” then the output will appear as a “ 1.34 ”. Here, formatting decimals displays numbers with a certain number after the decimal point.

You can refer to the below screenshot for python decimal format.

Python decimal format

Python round numbers

To round numbers in python, we will use the round[] function. The round function will round off a number to a given number of digits and makes rounding of numbers easier.

Example:

number = 1.345
print[round[number]]

After writing the above code [python round numbers], Ones you will print “ number ” then the output will appear as a “ 1 ”. Here, the number 1.345 float number will be rounded to 1.

You can refer to the below screenshot for python round numbers.

Python round numbers

Limiting floats to two decimal points

The round[] function returns a floating-point number which will be rounded to specified numbers, and it will round the float to two decimal places.

Example:

my_float = 2.13456
limit_float = round[my_float, 2]
print[limit_float]

After writing the above code [limiting floats to two decimal points], Ones you will print “limit_float” then the output will appear as a “ 2.13 ”. Here, the round[number] with a float number and 2 as ndigits to round float to two decimal points.

You can refer to the below screenshot for python round numbers.

Limiting floats to two decimal points

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In this tutorial, we learned how to print 2 decimal places in python and also we covered the below topics:

• Python print 2 decimal places
• Python float precision truncate
• Python float precision ceil
• Python float precision floor
• Python decimal format
• Python round numbers
• Limiting floats to two decimal points

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