How to convert fraction to percent in Python?

Fractions are a part of a whole commodity that can be expressed in the form of a numerator divided by the denominator. A fraction is of the form \pm\frac{p}{q}     , where p<=q. 

There are various methods of converting between fractions and percentages. 

Method 1: 

Manual conversion of the fraction to percentage can be done by multiplying the rational number by 100. The obtained decimal number may be rounded up to the required number of digits by using the inbuilt math.round() function which has the following syntax:

round(number, digits)

# define a number
num = 1/3

# converting to decimal value
dec_num = num * 100

# rounding number to required number of decimal places 
print ("Decimal equivalent in %")

# round to 2 places
print (round(dec_num,2))

Output

Decimal equivalent in %
33.33

In case the numerator is absolutely divisible by denominator, the number is returned to 1 place of decimal.

# define a number
num = 2/4

# converting to decimal value
dec_num = num * 100

# rounding number to required number of decimal places 
print ("Decimal equivalent in %")

# round to 2 places
print (round(dec_num,4))

Output

Decimal equivalent in %
50.0

Method 2: 

The str.format() method is used to convert the number into a percentage, by specifying the number of digits to take after the decimal point. 

"{:.n%}".format(num)

• n represents the number of digits after the decimal point
• num represents the floating-point number expressed either as a decimal or a fraction

The special case where the denominator of the fraction is 1, that is, fractional numbers become equivalent to an integer value. 

# input an integer with denominator =1 
integer_num = 2 
print ("Converting number to percentage rounding to 0 place of decimal")
print ("{:.0%}".format(integer_num))

# input an negative integer with denominator =1 
integer_num = -7 
print ("Converting number to percentage rounding to 5 place of decimal")
print ("{:.5%}".format(integer_num))

Output

Converting number to percentage rounding to 0 place of decimal

# input an integer with denominator =1 
integer_num = 2 
print ("Converting number to percentage rounding to 0 place of decimal")
print ("{:.0%}".format(integer_num))

# input an negative integer with denominator =1 
integer_num = -7 
print ("Converting number to percentage rounding to 5 place of decimal")
print ("{:.5%}".format(integer_num))

200%
Converting number to percentage rounding to 0 place of decimal
-700.00000%

While converting integers, the number of decimal places does not play any role, since the number is directly multiplied by 100. The number of zeros appended to the number is equivalent to the number of decimal places chosen. 

The following Python code is used to convert a rational number to an equivalent percentage :

# input a fractional number
num = 1/3

# taking 0 places to decimal and convert it to decimal
print ("Converting number to percentage rounding to 0 place of decimal")
print ("{:.0%}".format(num))
num = -2/4

# taking 2 places to decimal and convert it to decimal
print ("Converting number to percentage rounding to 2 place of decimal")
print ("{:.2%}".format(num))

Output

Converting number to percentage rounding to 0 place of decimal
33%
Converting number to percentage rounding to 2 place of decimal
-50.00%