From: Guido van Rossum Date: Mon, 15 Oct 2001 15:53:58 +0000 (+0000) Subject: Note about fix in list comprehensions. X-Git-Tag: v2.2.1c1~1281 X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=a8bcf80e7bde79c722d4cb76ded118d9dd0ffbca;p=python Note about fix in list comprehensions. --- diff --git a/Misc/NEWS b/Misc/NEWS index 5c411f9797..b10f4401cc 100644 --- a/Misc/NEWS +++ b/Misc/NEWS @@ -22,6 +22,15 @@ Type/class unification and new-style classes Core +- A very subtle syntactical pitfall in list comprehensions was fixed. + For example: [a+b for a in 'abc', for b in 'def']. The comma in + this example is a mistake. Previously, this would silently let 'a' + iterate over the singleton tuple ('abc',), yielding ['abcd', 'abce', + 'abcf'] rather than the intended ['ad', 'ae', 'af', 'bd', 'be', + 'bf', 'cd', 'ce', 'cf']. Now, this is flagged as a syntax error. + Note that [a for a in ] is a convoluted way to say + [] anyway, so it's not like any expressiveness is lost. + - binascii has now two quopri support functions, a2b_qp and b2a_qp. - readline now supports setting the startup_hook and the pre_event_hook.