Decimal Functions in Python | Set 1

Python in its definition provides certain methods to perform faster decimal floating point arithmetic using the module “decimal”.

Important operations on Decimals

1. sqrt() :- This function computes the square root of the decimal number.

2. exp() :- This function returns the e^x (exponent) of the decimal number.

 # Python code to demonstrate the working of  # sqrt() and exp()    # importing "decimal" module to use decimal functions import decimal    # using exp() to compute the exponent of decimal number a = decimal.Decimal(4.5).exp()    # using sqrt() to compute the square root of decimal number b = decimal.Decimal(4.5).sqrt()    # printing the exponent print ("The exponent of decimal number is : ",end="") print (a)    # printing the square root print ("The square root of decimal number is : ",end="") print (b)

Output:

The exponent of decimal number is : 90.01713130052181355011545675
The square root of decimal number is : 2.121320343559642573202533086

3. ln() :- This function is used to compute natural logarithm of the decimal number.

4. log10() :- This function is used to compute log(base 10) of a decimal number.

 # Python code to demonstrate the working of  # ln() and log10()    # importing "decimal" module to use decimal functions import decimal    # using ln() to compute the natural log of decimal number a = decimal.Decimal(4.5).ln()    # using sqrt() to compute the log10 of decimal number b = decimal.Decimal(4.5).log10()    # printing the natural logarithm print ("The natural logarithm of decimal number is : ",end="") print (a)    # printing the log10 print ("The log(base 10) of decimal number is : ",end="") print (b)

Output:

The natural logarithm of decimal number is : 1.504077396776274073373258352
The log(base 10) of decimal number is : 0.6532125137753436793763169118

5. as_tuple() :- Returns the decimal number as tuple containing 3 arguments, sign(0 for +, 1 for -), digits and exponent value.

6. fma(a,b) :- This “fma” stands for fused multiply and add. It computes (num*a)+b from the numbers in argument. No rounding of (num*a) takes place in this function.

Example :

decimal.Decimal(5).fma(2,3) --> (5*2)+3 = 13
 # Python code to demonstrate the working of  # as_tuple() and fma()    # importing "decimal" module to use decimal functions import decimal    # using as_tuple() to return decimal number as tuple a = decimal.Decimal(-4.5).as_tuple()    # using fma() to compute fused multiply and addition b = decimal.Decimal(5).fma(2,3)    # printing the tuple print ("The tuple form of decimal number is : ",end="") print (a)    # printing the fused multiple and addition print ("The fused multiply and addition of decimal number is : ",end="") print (b)

Output:

The tuple form of decimal number is : DecimalTuple(sign=1, digits=(4, 5), exponent=-1)
The fused multiply and addition of decimal number is : 13

7. compare() :- This function is used to compare decimal numbers. Returns 1 if 1st Decimal argument is greater than 2nd, -1 if 1st Decimal argument is smaller than 2nd and 0 if both are equal.

8. compare_total_mag() :- Compares the total magnitute of decimal numbers. Returns 1 if 1st Decimal argument is greater than 2nd(ignoring sign), -1 if 1st Decimal argument is smaller than 2nd(ignoring sign) and 0 if both are equal(ignoring sign).

 # Python code to demonstrate the working of  # compare() and compare_total_mag()    # importing "decimal" module to use decimal functions import decimal    # Initializing decimal number a = decimal.Decimal(9.53)    # Initializing decimal number b = decimal.Decimal(-9.56)    # comparing decimal numbers using compare() print ("The result of comparison using compare() is : ",end="") print (a.compare(b))    # comparing decimal numbers using compare_total_mag() print ("The result of comparison using compare_total_mag() is : ",end="") print (a.compare_total_mag(b))

Output:

The result of comparison using compare() is : 1
The result of comparison using compare_total_mag() is : -1

9. copy_abs() :- This function prints the absolute value of decimal argument.

10. copy_negate() :- This function prints the negation of decimal argument.

11. copy_sign() :- This function prints the first argument by copying the sign from 2nd argument.

 # Python code to demonstrate the working of  # copy_abs(),copy_sign() and copy_negate()    # importing "decimal" module to use decimal functions import decimal    # Initializing decimal number a = decimal.Decimal(9.53)    # Initializing decimal number b = decimal.Decimal(-9.56)    # printing absolute value using copy_abs() print ("The absolute value using copy_abs() is : ",end="") print (b.copy_abs())    # printing negated value using copy_negate() print ("The negated value using copy_negate() is : ",end="") print (b.copy_negate())    # printing sign effected value using copy_sign() print ("The sign effected value using copy_sign() is : ",end="") print (a.copy_sign(b))

Output:

The absolute value using copy_abs() is : 9.5600000000000004973799150320701301097869873046875
The negated value using copy_negate() is : 9.5600000000000004973799150320701301097869873046875
The sign effected value using copy_sign() is : -9.5299999999999993605115378159098327159881591796875

12. max() :- This function computes the maximum of two decimal numbers.

13. min() :- This function computes the minimum of two decimal numbers.

 # Python code to demonstrate the working of  # min() and max()    # importing "decimal" module to use decimal functions import decimal    # Initializing decimal number a = decimal.Decimal(9.53)    # Initializing decimal number b = decimal.Decimal(7.43)    # printing minimum of both values print ("The minimum of two numbers is : ",end="") print (a.min(b))    # printing maximum of both values print ("The maximum of two numbers is : ",end="") print (a.max(b))

Output:

The minimum of two numbers is : 7.429999999999999715782905696
The maximum of two numbers is : 9.529999999999999360511537816

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