2.2 features

Cliff Crawford cjc26 at nospam.cornell.edu
Thu Jul 26 17:40:05 CEST 2001


* Tom Good <Tom_Good1 at excite.com> menulis:
| 
| #------ begin code
| 
| def genWhile(g, condition):
|     """
|     run generator g while 'condition' is true.
|     Condition is a partial expression string such as "< 10"
|     to be evaluated with g.next() as the left side
|     """
|     while 1:
|         next = g.next()
|         if eval("next " + condition):
|             yield next
|         else:
|             raise StopIteration
| 
| #------ end code
| 
| Then you can say, for example:
| 
| >>> g = fib()
| >>> [x for x in genWhile(g, "< 50")]
| 
| [1, 1, 2, 3, 5, 8, 13, 21, 34]
| 
| ...to get the Fibonacci numbers that are less than 50.

This is neat, but I think passing in a function to test the condition
would be cleaner than passing in a string.  Like this:

def genWhile(g, condition):
    while 1:
        next = g.next()
        if condition(next):
            yield next
        else:
            return

[x for x in genWhile(fib(), lambda f: f < 50)]


-- 
Cliff Crawford            http://www.sowrong.org/
A sign should be posted over every campus toilet:
"This flush comes to you by courtesy of capitalism." 
                                 -- Camille Paglia



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