Conditional statements such as Python if-elif-else are an essential part of decision making in any programming language. In Python, conditional statements allow us to evaluate different conditions and execute statements or a group of statements depending on whether the condition was True or False. Only one block among several, yes. Elif. Else Blocks is executed depending on the condition. The elif block runs when the specified condition is set to True. The if. The else statement evaluates the test expression and executes the body of if the test condition is True only if the test condition is True. The if. Elif. else statement is used in Python for decision making.
If the simple block code is to be executed, if the condition is true, a statement is used. Here the mentioned condition applies, otherwise the block code will not run. Core Python does not provide switch instructions or cases as in other languages, but we can use if. Elif. -Instructions for simulating the switching case as follows – We can summarize the flow of if-else statements in the following flowchart. In Python, the body of the if statement is specified by the indent. The body begins with a depression and the first unindented line marks the end. The else statement is typically used in conjunction with the if statement. An if statement can have only one other statement.
When used with elif statements, their body is executed if all conditions of the if and elif statements are False. Python allows us to write an entire if statement on a line. Use the elif statement to specify a new condition to test whether the first condition is incorrect. If the expression is set to False under the if statement, the program checks for expressions in subsequent elif blocks. For example, we can check if the variable x is greater than the variable y and print a message, and if it is not greater than y, we can check if it is less than y and print another message. Since z is equal to 3, the first condition is False, so it moves to the next condition. The next condition is for True. Therefore, the corresponding print statement is executed. If the condition of if is False, the condition of the next elif block, etc., is verified. In the example above, the condition if price >= 100 is False, so the else block is executed.
The else block can also contain multiple statements with the same indent. Otherwise, IndentationError is thrown. First, the expression is evaluated. If the expression is true, the statements in if are executed and the else block is ignored. If the expression is false, the else block statement is executed. In the example above, the elif conditions are applied after the if condition. Python evaluates the if condition, and when evaluated at False, it evaluates the elif blocks and executes the elif block, whose expression is evaluated at True. If more than one elif condition is set to True, the first elif block is executed. You can use the elif statement to check for TRUE in multiple expressions and execute a block of code when one of the conditions is TRUE. Typically, the nested if-else statement is used when we want to check multiple conditions. Conditions are executed from top to bottom and check each condition to see if it is true or not. If a true condition is found, the statement block associated with the condition is executed, otherwise it moves to the next condition.
Here is the syntax: In this example, we check whether a number is even or odd. In logic, we have verified that if the modulus of a number is zero, it is even. Indeed, all even numbers, divided by 2, have a remainder of 0. We checked the module of 0 in a separate statement because dividing by zero gives a plotting error. In the following example, you define two variables, room and area. They then construct if-elif-else and if-else conditions for space and surface, respectively. The IF statement can also be checked in another if statement. This conditional statement is called a nested if statement. This means that the internal If condition is only verified if the external condition is true, allowing us to see several conditions that must be met. If the test expression is set to False, the statement(s) are not executed. Python supports nested if, elif, and else conditions.
The internal condition must have a higher indentation than the external condition, and all statements in a block must have the same indentation. Indentation has a special meaning in Python. It is used to define a block of code (often called a suite). Rough indented instructions at the same level are considered part of the same block. In the above case, expression specifies conditions based on the Boolean expression. When a Boolean expression is evaluated, it produces true or false. If the expression is true, the same number of indented statements are executed. This group of statements is called a block.
Because the expression under the if statement is False, the print statement is ignored in its body. On the other hand, because the expression under the elif statement is True, your body`s print statement is executed. With the if statement, the else condition can optionally be used to define another block of statements to execute when the Boolean expression of the if condition is set to False. To join two or more conditions in a single if statement, use logical operators, namely and, or and not. Here, the program evaluates the test expression and executes one or more statements only if the test expression is True. In the above syntax, expression1 is checked first, if it is set to true, then the program control passes to the next if – otherwise part goes to the last else statement and executes statement_7, statement_8, etc. In if – else if expression2, true then evaluates statement_3, statement_4 otherwise statement_5 is executed statement_6 is executed. See the following example. Note that the body of the if block is the sequence of indented instructions. The colon at the end of indicates the beginning of the if statement. At the top, the if condition contains multiple statements with the same indent.
If all statements are not in the same indent, either in space or in a tab, an IdentationError is thrown. Elif is short for else if. It allows us to search for multiple expressions. Any Boolean expression that is set to True or False appears after the if keyword. Use the : icon and press Enter after printing to start a block with an enlarged indent. One or more statements written with the same indent are executed when the Boolean expression is set to True. In Python yes. else , if has two blocks, one after the expression and another after the else clause. Here is the syntax. Here we need to check a condition and make the decision accordingly. This is where control structures come into play. A control tree redirects the order in which statements are executed in a program.
In this tutorial, we learned how to control the execution flow using if-else statements. Using conditional statements helps us write meaningful programs. These instructions can be nested to solve complex problems. Statements with the same indentation level as if condition are ignored in the if block. You will consider from the if condition. In Python we can use if, if-else, if-elif-else or switch statements to control the execution of the program. Loops are another way to control execution flow. In this blog, we will mainly focus on if-else and its derivatives. An if block can contain multiple elif statements, which means you can test even more conditions. An else statement can be combined with an if statement.
An else statement contains the block of code that is executed when the conditional expression of the if statement resolves to 0 or false. Note that the second Elif was not executed as the first Elif evaluated as true. The conditional expression (sometimes called the ternary operator) allows us to select one of two statements based on the specified condition. You can nest statements within a code block to start a new code block, as long as they follow their respective indents. This means that if the if statement is false, the next elif expression is checked. If an expression is true, the control exits the if-else block. This article explains how to use if, elif, and else conditional statements in Python. In the following example, we use the if statement to test whether variable y is greater than variable x.
And if true, the print statement is executed in the body of the if statement. Unlike other programming languages, Python does not have a `switch` statement. You can use if. Elif. ELIF sequence as a substitute. If either of the first two statements is set to True, the else statement is not executed. For example, if we change the value of variable x to 25. This means that the elif statement is now True and therefore the else part is not executed. At most, a block would be executed.
If nothing else is specified and all the statements are incorrect, none of the blocks will be executed. The statements or group of statements are executed if the expression returns the Boolean value of True. The indent specifies the beginning of the body of the if statement. The If statement without indentation returns a syntax error. The Python if statement is identical to other programming languages. It conditionally executes a series of statements based on the value of a logical expression. By default, statements are executed sequentially. Sequential order means that statements are executed sequentially in the order in which they are written. In the example above, the age is set to 38, so the first expression (age >= 11) is True and the associated print statement returns the string “You are eligible to see the football game.” After that, the program control moves to the next if statement and the condition (38 is outside =60) is mapped and outputs “The price of the Tic kit is $12”.
