Python Programming – Expressions

You can learn about Operators in Python Programs with Outputs helped you to understand the language better.

Also Read: Java Program to Convert Kilogram to Pound and Pound to Kilogram

Python Programming – Expressions

The expression consists of a combination of values, which can be constant values, such as a string (” Shiva ” ) or a number (12), and operators, which are symbols that act on the values in some way. The following are the examples of expression:
10 – 4
11 * ( 4 + 5 )
X – 5
a / b
In other words, the expression consists of one or more operands and one or more operators linked together to compter a value. for example:
a = 5 # assume a = 5
a + 2

is a larger expression that results in the sum of the value in the variable a is also an expression as is the constant 2 since they both represent the value. expression value, in turn, can act as Operands for Operators. For example, 9+6and 8+5+2 are two expressions that will result in a value of 15. taking another example, 6.0/5+(8-5.0) is an expression in which values of different data types are used. these types of expressions are also known as mixed types of expression. when mixed types expressions are evaluated, python promotes the result of the lower data type of higher data type, i.e., to float. So, the result of the above-mentioned expression will be 4.2. There is known as implicit typecasting. Implicit typecasting is done without any intimation to the user. sometimes, you may want to perform a type of conversion ourselves. the programmer may instruct the Python interpreter to convert one type of data to another type, which is known as explicit conversion.
the float() function convert an int into float. python also provides int () and long () functions () that can be used to coverlet numbers into ints and longs,respectvly.
for example,

>>> float (22)
>>> int(4.8)

Expression can also contain another expression. When you have an expression consisting of subexpression(s), Python decides the order of operations based on the precedence of the operator. When an expression contains two different kinds of operators, the order in which the operators should be applied

is known as Operator Precedence. A higher precedence operator is applied before a lower precedence operator. When an expression contains two operators with the same precedence, the order in which the operators should be applied first is known as Associativity. Operator associativity determines the order of evaluation when the operators are of the same precedence and are not grouped by parentheses.
An operator may be left-associative or right-associative. In the left-associative, the operator appearing on the left side will be evaluated first, while in the right-associative, the operator appearing on the right will be evaluated first. In Python ‘=’ and ‘**’ are right-associative. The following list describes the basic rules of operator precedence in Python:

(a) Expressions are evaluated from left to right.

(b) Exponentiation, multiplication, and division are performed before addition and subtraction.

(c) Expressions in parentheses are evaluated first. Parentheses can be used to group terms in an expression to provide control over the order in which the operations are performed.

(d) Mathematical expressions are performed before Boolean expressions ( and, or, not). Table 4.5 summarizes the precedence of operators from higher precedence to lower precedence.
When at least one of the operands is itself an expression (as in 2 * 7 + 5), the expression is a com¬pound expression. Python follows the standard mathematical order of operations, so 2 * 7 + 5 is equivalent to (2*7) + 5.

Operator Name Operators Symbols
Exponentiation **
Unary plus and minus +, –
Multiply, divide, modulus, floor division *,/,%,//
Addition and subtraction +, –
Relational (comparison) operators <,<=,>,>=
Equality operators ==, !=
Assignment operators %=, /=,//=, -=, +=, *=
Logical operators not, and, or

Let’s Try

Evaluate the following expression with precedence of operator:

x = 2* 3/ 5 + 10 //3 -1 x = 3* 3/ 2 + 9 //3 – 2
print(x) print(x)

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