Thomas Passin wrote:
On 4/2/2024 1:47 PM, Piergiorgio Sartor via Python-list wrote:
On 02/04/2024 19.18, Stefan Ram wrote:
Some people can't believe it when I say that chatbots improve
my programming productivity. So, here's a technique I learned
from a chatbot!
It is a structured "break". "Break" still is a kind of jump,
you know?
So, what's a function to return the first word beginning with
an "e" in a given list, like for example
[ 'delta', 'epsilon', 'zeta', 'eta', 'theta' ]
? Well it's
def first_word_beginning_with_e( list_ ):
for word in list_:
if word[ 0 ]== 'e': return word
. "return" still can be considered a kind of "goto" statement.
It can lead to errors:
def first_word_beginning_with_e( list_ ):
for word in list_:
if word[ 0 ]== 'e': return word
something_to_be_done_at_the_end_of_this_function()
The call sometimes will not be executed here!
So, "return" is similar to "break" in that regard.
But in Python we can write:
def first_word_beginning_with_e( list_ ):
return next( ( word for word in list_ if word[ 0 ]== 'e' ), None )
Doesn't look a smart advice.
. No jumps anymore, yet the loop is aborted on the first hit
It's worse than "not a smart advice". This code constructs an
unnecessary tuple, then picks out its first element and returns that.
I don't think there's a tuple being created. If you mean:
( word for word in list_ if word[ 0 ]== 'e' )
...that's not creating a tuple. It's a generator expression, which
generates the next value each time it's called for. If you only ever
ask for the first item, it only generates that one.
When I first came across them, I did find it a bit odd that generator
expressions look like the tuple equivalent of list/dictionary
comprehensions.
FWIW, if you actually wanted a tuple from that expression, you'd need to
pass the generator to tuple's constructor:
tuple(word for word in list_ if word[0] == 'e')
(You don't need to include an extra set of brackets when passing a
generator a the only argument to a function).
--
Mark.
--
https://mail.python.org/mailman/listinfo/python-list
