control structures and functions "fr"but the global language variable used in the print_digits(function would remain unchanged as "enfor nontrivial programs it is best not to use global variables except as constantsin which case there is no need to use the global statement lambda functions |lambda functions are functions created using the following syntaxlambda parametersexpression the parameters are optionaland if supplied they are normally just commaseparated variable namesthat ispositional argumentsalthough the complete argument syntax supported by def statements can be used the expression cannot contain branches or loops (although conditional expressions are allowed)and cannot have return (or yieldstatement the result of lambda expression is an anonymous function when lambda function is called it returns the result of computing the expression as its result if the expression is tuple it should be enclosed in parentheses here is simple lambda function for adding an (or notdepending on whether its argument is lambda "if = else "sthe lambda expression returns an anonymous function which we assign to the variable any (callablevariable can be called using parenthesesso given the count of files processed in some operation we could output message using the (function like thisprint("{ file{ processedformat(counts(count))lambda functions are often used as the key function for the built-in sorted(function and for the list sort(method suppose we have list of elements as -tuples of (groupnumbername)and we wanted to sort this list in various ways here is an example of such listelements [( "mg")( "na")( "li")( "be")if we sort this listwe get this result[( 'li')( 'na')( 'be')( 'mg')sorted( we saw earlier when we covered the sorted(function that we can provide key function to alter the sort order for exampleif we wanted to sort the list by number and namerather than the natural ordering of groupnumberand namewe could write tiny functiondef ignore ( )return [ ] [ ]which could be provided as the key function creating lots of little functions like this can be inconvenientso frequently used alternative is lambda functiongenerator functions