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Date: Sun, 21 Apr 2013 09:09:20 -0500
From: "Robert Yacobellis" <ryacobellis@luc.edu>
To: <python-list@python.org>
Subject: suggestion for a small addition to the Python 3 list class
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Greetings,
=20
I'm an instructor of Computer Science at Loyola University, Chicago, and I =
and Dr. Harrington (copied on this email) teach sections of COMP 150, =
Introduction to Computing, using Python 3.  One of the concepts we teach =
students is the str methods split() and join().  I have a suggestion for a =
small addition to the list class: add a join() method to lists.  It would =
work in a similar way to how join works for str's, except that the object =
and method parameter would be reversed: <list object>.join(<str object>).
=20
Rationale: When I teach students about split(), I can intuitively tell =
them split() splits the string on its left on white space or a specified =
string.  Explaining the current str join() method to them doesn't seem to =
make as much sense: use the string on the left to join the items in the =
list??  If the list class had a join method, it would be more intuitive to =
say "join the items in the list using the specified string (the method's =
argument)."  This is similar to Scala's List mkString() method.
=20
I've attached a proposed implementation in Python code which is a little =
more general than what I've described.  In this implementation the list =
can contain elements of any type, and the separator can also be any data =
type, not just str.
=20
I've noticed that the str join() method takes an iterable, so in the most =
general case I'm suggesting to add a join() method to every Python-provided=
 iterable (however, for split() vs. join() it would be sufficient to just =
add a join() method to the list class).
=20
Please let me know your ideas, reactions, and comments on this suggestion.
=20
Thanks and regards,
Dr. Robert (Bob) Yacobellis

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<DIV>Greetings,</DIV>
<DIV>&nbsp;</DIV>
<DIV>I'm an instructor of Computer Science at Loyola University, Chicago, =
and I and Dr. Harrington (copied on this email) teach sections of COMP =
150, Introduction to Computing, using Python 3.&nbsp; One of the concepts =
we teach students is the str methods split() and join().&nbsp; I have a =
suggestion for a small addition to the list class: add a join() method to =
lists.&nbsp; It would work in a similar way to how join works for str's, =
except that the object and method parameter would be reversed: &lt;list =
object&gt;.join(&lt;str object&gt;).</DIV>
<DIV>&nbsp;</DIV>
<DIV>Rationale: When I teach students about split(), I can intuitively =
tell them split() splits the string on its left on white space or a =
specified string.&nbsp; Explaining the current str join() method to them =
doesn't seem to make as much sense: use the string on the left to join the =
items in the list??&nbsp; If the list class had a join method, it would be =
more intuitive to say "join the items in the list using the specified =
string (the method's argument)."&nbsp; This is similar to Scala's =
List&nbsp;mkString() method.</DIV>
<DIV>&nbsp;</DIV>
<DIV>I've attached a proposed implementation in Python code which is a =
little more general than what I've described.&nbsp; In this implementation =
the list can contain elements of any type, and the separator can also be =
any data type, not just str.</DIV>
<DIV>&nbsp;</DIV>
<DIV>I've noticed that the str join() method takes an iterable, so in the =
most general case I'm suggesting to add a join() method to every Python-pro=
vided iterable (however, for split() vs. join() it would be sufficient to =
just add a join() method to the list class).</DIV>
<DIV>&nbsp;</DIV>
<DIV>Please let me know your ideas, reactions,&nbsp;and comments on this =
suggestion.</DIV>
<DIV>&nbsp;</DIV>
<DIV>Thanks and regards,</DIV>
<DIV>Dr. Robert (Bob) Yacobellis</DIV></BODY></HTML>

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