If, Else, and Elif Statements
If
if
statements do something when a condition is met. For example:if x == 5: print("x is equal to 5")
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Else
You can also tell a computer what to do if the condition isn't met by using
else
. if x == 3: print("x is equal to 3") else: print("x is NOT equal to 3")
Elif
You can also introduce new “if” statements when you use an “else”. These are called "else if" statements, which we write as
elif
. You can have multiple elif
statements after an if
statement, and you can also have a final else
statement after all the elif
statements, as shown below.if x == 5: print("x is equal to 5") elif x == 6: print("x is equal to 6") elif x == 7: print("x is equal to 7") else: print("x is not equal to 5, 6, or 7")
Indentation matters in Python! Indentation is useful to programmers so we can see the structure and hierarchy of the code. If you don't indent properly, your program might not run, or it might run incorrectly. In the case of if statements, whatever is inside the
if
block, elif
block, or else
block must be indented accordingly.Remember: you can use an
if
statement without an else
or elif
statement., but you cannot use an else
or elif
statement without an if
statement. Your code will error if there isn’t an if
statement to start off your elif
statements or your else
statements. After all, it doesn’t make sense to say “else” or “else if” without an “if” before them.
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