{"id":7453,"date":"2020-07-28T15:18:46","date_gmt":"2020-07-28T15:18:46","guid":{"rendered":"https:\/\/www.askpython.com\/?p=7453"},"modified":"2022-08-06T13:29:23","modified_gmt":"2022-08-06T13:29:23","slug":"python-decimal-module","status":"publish","type":"post","link":"https:\/\/www.askpython.com\/python-modules\/python-decimal-module","title":{"rendered":"Python decimal module – 7 functions you need to know!"},"content":{"rendered":"\n

Hey, all! In this article, we will have a look at one of the interesting modules – The Python Decimal module<\/strong>.<\/p>\n\n\n\n

Be it any domain, we do come across the need to search for functions to perform mathematical operations. Python decimal module serves us with all the mathematical functions we need.<\/p>\n\n\n\n

So, let us get started!<\/p>\n\n\n\n

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Understanding the Python decimal module<\/h2>\n\n\n\n

Python decimal module contains various functions to handle numeric data and perform different mathematical operations on it. Using the decimal module, we can handle decimal numbers efficiently throughout our program.<\/p>\n\n\n\n

The decimal module<\/code> provides us with functions to control and overcome the problem of precision in the decimal values.<\/p>\n\n\n\n

Having understood the need of Decimal module, let us now have a look at some of the important functions offered by the module.<\/p>\n\n\n\n

In order to use the functions, we need to import the module as shown below:<\/p>\n\n\n

\nimport decimal\n<\/pre><\/div>\n\n\n
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The Decimal Module Functions and Implementation<\/h2>\n\n\n\n
Different arithmetic operations can be performed on the decimal or numeric data to boost the outcome. <\/p>\n\n\n\n
We can define the decimal point numbers using the decimal.Decimal() function<\/code> as shown below–<\/p>\n\n\n\n
Syntax:<\/strong><\/p>\n\n\n
\nimport decimal\nvariable = decimal.Decimal(decimal-number)\n<\/pre><\/div>\n\n\n
Further, we can control the precision value of the results of the decimal point numbers using an in-built function by the decimal module — decimal.getcontext().prec<\/code> function.<\/p>\n\n\n\n
Syntax:<\/strong><\/p>\n\n\n
\ndecimal.getcontext().prec = precision value\n<\/pre><\/div>\n\n\n
The below-explained functions help us perform decimal point arithmetic operations in an efficient manner and at a great pace.<\/p>\n\n\n\n
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1. The exp() function – Exponent calculation<\/h3>\n\n\n\n
The exp() function<\/code> computes the exponent value i.e. e^x<\/strong> of the particular decimal point number passed to it.<\/p>\n\n\n\n
Syntax:<\/strong><\/p>\n\n\n
\ndecimal.Decimal(decimal-number).exp()\n<\/pre><\/div>\n\n\n
Example:<\/strong><\/p>\n\n\n
\nimport decimal as d\n\nd.getcontext().prec = 5\n\n#Intializing with an addition operation\nval = d.Decimal(12.201) + d.Decimal(12.20)\n\n#Calculating exponential of the decimal value\nexp = val.exp()\n\n#variable with no calculations\nno_math = d.Decimal(1.131231)\n\nprint("Sum: ",val)\nprint("Exponential: ", exp)\nprint(no_math)\n<\/pre><\/div>\n\n\n
Output:<\/strong><\/p>\n\n\n
\nDecimal Number:  24.401                                                                                                       \n3.9557E+10                                                                                                                    \n1.131231000000000097571728474576957523822784423828125   \n<\/pre><\/div>\n\n\n
Notice how the total number of digits in our output are 5? That’s because of the precision value that we set up here. <\/p>\n\n\n\n
One thing to remember is that the precision value applies when you perform mathematical operations on two decimals not when you directly initiate a variable with the values as shown with the “no_math” variable above.<\/p>\n\n\n\n
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2. The sqrt() function – Square Root<\/h3>\n\n\n\n
The sqrt() function calculates and returns the square root value <\/strong>of the passed decimal number to it.<\/p>\n\n\n\n
Syntax:<\/strong><\/p>\n\n\n
\ndecimal.Decimal(decimal-number).sqrt()\n<\/pre><\/div>\n\n\n
Example:<\/strong><\/p>\n\n\n
\nimport decimal as d\n\nd.getcontext().prec = 3\n\nval = d.Decimal(122.20)\nsqrt = val.sqrt()\nprint("Decimal Number: ",val)\nprint("Square root of the decimal number: ",sqrt)\n<\/pre><\/div>\n\n\n
Output:<\/strong><\/p>\n\n\n
\nDecimal Number:  122.2000000000000028421709430404007434844970703125\nSquare root of the decimal number:  11.1\n<\/pre><\/div>\n\n\n
Again, note how the declared value contains the complete decimal number while the computed value follows our precision set of 3 digits.<\/p>\n\n\n\n
To find more mathematical operations, read our article on math module in Python<\/a><\/p>\n\n\n\n
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3. Logarithmic functions<\/h3>\n\n\n\n
Decimal module provides us with the below functions to calculate the logarithmic values of the decimal point numbers–<\/p>\n\n\n\n