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Hello welcome to this tutorial on IF statement

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conditional statements.

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Give us an ability to check conditions and change the behavior of the program accordingly and if statements

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are also known as Control floor statements which help us to run a particular chord.

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Only when a certain condition is met this is the syntax for the if statement if it is the key word then

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we have a boolean expression and then a set of statements.

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The first line of statement that is the if condition is known as if clause and the condition your is

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a boolean expression that is evaluated to either true or false and in the next line.

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We have a block of statements and notice the colon after the if clause in the first line.

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This is very important because it separates the if clause with the body that is the block of statements

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here.

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Next the line after the colon must be indented.

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That means the block of code should be positioned by the same amount to the right of the.

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If keyword and Biden recommends to indent each statement in the block by four spaces so beginning from

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the if key word.

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We need to indent each statement by Force bases.

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So you need to leave four spaces and then you can type your code after that.

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So all of this code gets executed.

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If the if condition is true and these statements followed by the if clause which are not indented that

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means the statement here.

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For example the non belong to the if block so these statements are not part of the block.

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So as a result it will always execute no matter whether the condition in the if clause is true or false.

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So let's now look at some examples.

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I have the if clause here.

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This boolean expression age is less than or equal to fly.

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And if this condition is true the print function print the text here.

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And as you can see there is only one statement in this if clause going to the next example.

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I have two variables and a is assigned to two and then B is assigned to 5 and the boolean expression

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your checks.

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If it is greater than B Since 2 is not greater than 5 the indented code here is not executed.

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The condition is false and this block of code is not executed.

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So decontrol goes to the first UN indented statement in the program and this is the statement and the

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program flaw goes like this.

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So here I assign why you do to the variable each and then using the if condition.

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I'm going to check if this particular boolean expression is true or not and there's one statement in

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the if clause notice the indentation here I have left some spaces to the right of the if keyword so

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that this gets executed.

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If the condition is true so now let execute this piece of code.

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So this condition is true and the text has been printed.

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Let's consider in another example.

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So in this example I have assigned devalued tend to debatable each and the boolean expression in the

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if clause checks if the variable is less than or equal to 5.

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And if this boolean expression is true the print function print this text or another print function

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but just not indented which means it does not belong to the if clause and it gets executed no matter

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whether the condition in the clause is true or not.

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So let's execute this piece of code devalue 10 is not less than equal to 5.

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That means the boolean expression used is false.

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So this print function is not executed.

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The next statement in the program which is not indented is the print function so the program executes

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this line of code.

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It does now discuss another exam but so I have a variable flag that is assigned to the Boolean value

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true and then I have the if statement the if statement checks if the variable flag is true or not.

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And if this is true it prints this text we have discussed before that the if statement always checks

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if the condition is true only if the condition is true the statement within the if block are executed

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or not executed at all.

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So comparing variable flag here with the Boolean value true is redundant so we can put this if statement

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like this.

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If flat and then print.

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We'll see.

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So in this if statement we have simply parsed the variable flag to the if clause because if always checks

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if the condition is true.

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So here in this example I have assigned the Boolean value true to the variable flag and in the if condition

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I have simply parsed the variable flag.

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That's because the if condition gets executed only if this particular condition is true we don't have

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to compare the variable flag with the Boolean value true and if this is true the print function prints

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the text.

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So let's execute this set of.

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So this is the output.

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Now we have discussed in previous tutorials that in Python the value 0 evaluates to false.

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Similarly an empty string evaluates to false and empty list evaluate to false and the integer 1 2 3

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for any integer greater than 0 evaluates to true so.

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So here to the if a word I have passed an empty string and an empty string and Python evaluates true

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false.

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So this brain function will not get executed.

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So let's execute this in and check.

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As you can see this is false.

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An empty string evaluates to file and so d if block did not get executed.