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if...else statement
Decision making is the most important aspect of almost all the programming languages. As the name implies, decision making allows us to run a particular block of code for a particular decision. Here, the decisions are made on the validity of the particular conditions. Condition checking is the backbone of decision making. if (condition) { # block of code to be executed if the condition is true } Python supports the usual logical conditions from mathematics Ifcondition evaluates to true, statement_1 is executed; otherwise, statement_2 is executed. statement_1 and statement_2 can be any statement, including further nested if statements.

You may also compound the statements using else if to have multiple conditions tested in sequence, as follows:

if (20 > 18) { printf("20 is greater than 18"); } In the case of multiple conditions only the first logical condition which evaluates to true will be executed. To execute multiple statements, group them within a block statement ({ ... }) . In general, it's good practice to always use block statements, especially when nesting if statements: if (condition) { // block of code to be executed if the condition is true } else { // block of code to be executed if the condition is false } It is advisable to not use simple assignments in a conditional expression, because the assignment can be confused with equality when glancing over the code. For example, do not use the following code: a = 200 b = 33 if b > a: print("b is greater than a") elif a == b: print("a and b are equal") else: print("a is greater than b") In this example a is greater than b, so the first condition is not true, also the elif condition is not true, so we go to the else condition and print to screen that "a is greater than b". a = 200 b = 33 if b > a: print("b is greater than a") else: print("b is not greater than a"