<[EMAIL PROTECTED]> wrote in message news:[EMAIL PROTECTED] | hi all | i want to check a condition and if true should return a filename | string from a list.if the condition is false i am returning a | "" (string literal).. | | retv="" | if somecondition: | retv=mylist[x] | ... | return retv | | | The calling function will check the return value and print the | filename if it is not """. | in the calling function i can code | if returnval !="": | print "filename is:",returnval | else: | print "no filename found" | | what i want to know is ,should i rewrite the if returnval !="" as | | if returnval: | print "filename is:",returnval | else: | print "no filename found"
In this situation, where returnval must be a string, the two are equivalent. So I consider the shorter, more efficient form stylistically better. In situations where various null or non-null conditions are not equivalent, one should use the one that is correct for the situation. | or is the way i coded the right way ? i am little confused here | Someone suggested that i make a variable retv None and if the | condition true then set retv as filename , | | retv=None | if somecondition: | retv=mylist[x] | | ... | return retv | | which approach is correct..? As long as the function returns are documented and the behavior matches the documentation and the calling code matched the behavior, both are 'correct'. I see this as stylistic preference. I can think of situations where a null string might be more useful that None, so I might go with that. Others might think of situations where a None return might be better. But a function cannot satisfy all possible callers ;-) (The is one problem with writing library code.) Terry Jan Reedy -- http://mail.python.org/mailman/listinfo/python-list
