[Tutor] input with default value option

[Danny Yoo]

> With raw_input(), it allows to input value. Can it be used to input 
> value with default value option?

Hi Phon,

We can build your own function to do this.  Bob showed how to set up code 
so that the default's taken if the user just presses enter in his reply. 
Let's take a look at it again:

###########################################
response = raw_input("Enter some data:")
if not response: response = "default value"
###########################################


We can capture this as a function that takes in a question and a default 
answer:

##################################
def ask(question, default):
     response = raw_input(question)
     if not response:
         response = default
     return response
##################################


And now we have something that acts like raw_input(), but also gives the 
user the ability to get a default:

######
>>> ask("favorite color?", "Blue.  No yellow -- aaaugh!")
favorite color?red
'red'
>>> ask("favorite color?", "Blue.  No yellow -- aaaugh!")
favorite color?
'Blue.  No yellow -- aaaugh!'
>>> 
######

(In the second call to ask(), I just pressed enter.)


Does this make sense?