{"id":115442,"date":"2020-07-15T06:42:11","date_gmt":"2020-07-15T06:42:11","guid":{"rendered":"https:\/\/blog.finxter.com\/?p=10805"},"modified":"2020-07-15T06:42:11","modified_gmt":"2020-07-15T06:42:11","slug":"python-ternary-elif","status":"publish","type":"post","link":"https:\/\/sickgaming.net\/blog\/2020\/07\/15\/python-ternary-elif\/","title":{"rendered":"Python Ternary Elif"},"content":{"rendered":"

Summary<\/strong>: To use an elif branch in the ternary operator, use another ternary operator as the result of the else branch (nested ternary operator). The nested ternary operator x if c0 else y if c1 else z<\/code> returns x<\/code> if condition c0<\/code> is met, else if (elif) condition c1<\/code> is met, it returns y<\/code>, else it returns z<\/code>.<\/p>\n

\"Python<\/figure>\n

Problem<\/strong>: You may have seen the ternary operator x if c else y<\/code>. Is there a similar ternary operator with an additional elif statement? In pseudocode, you want something like:<\/p>\n

# Pseudocode<\/code>\nx if c elif y0<\/strong> else y1<\/code><\/pre>\n
In other words: What’s the best way of extending the ternary operator to what you may call a “quaternary” operator?<\/em><\/p>\n
Background<\/strong>: The most basic ternary operator x if c else y<\/code> consists of three operands x<\/code>, c<\/code>, and y<\/code>. It is an expression with a return value. The ternary operator returns x<\/code> if the Boolean expression c<\/code> evaluates to True<\/code>. Otherwise, if the expression c<\/code> evaluates to False<\/code>, the ternary operator returns the alternative y<\/code>.<\/p>\n
Learn more about the ternary operator in our detailed blog article!<\/a><\/em><\/strong><\/p>\n
Example<\/strong>: Say, you want to write the following if-then-else condition in a single line of code:<\/p>\n
>>> x = 42\n>>> if x > 42:\n>>> print(\"no\")\n>>> elif x == 42:\n>>> print(\"yes\")\n>>> else:\n>>> print(\"maybe\")\nyes<\/pre>\n
The elif branch wins: you print the output \"yes\"<\/code> to the shell. <\/p>\n
But how to do it in a single line of code? Just use the ternary operator with an elif statement won’t work (it’ll throw a syntax error):<\/p>\n
\"\"<\/figure>\n
Method: Nested Ternary Operator<\/h2>\n
The answer is simple: nest two ternary operators like so:<\/p>\n
>>> print(\"no\") if x > 42 else print(\"yes\") if x == 42 else print(\"maybe\")\nyes<\/pre>\n
If the value x is larger than 42, we print “no” to the shell. Otherwise, we execute the remainder of the code (which is a ternary operator by itself). If the value x is equal to 42, we print “yes”, otherwise “maybe”.<\/p>\n
So by nesting multiple ternary operators, we can greatly increase our Python one-liner power!<\/p>\n
Try it yourself:<\/strong><\/p>\n