Path: csiph.com!fu-berlin.de!uni-berlin.de!not-for-mail From: gvim Newsgroups: comp.lang.python Subject: Why lambda in loop requires default? Date: Sun, 27 Mar 2016 02:46:08 +0100 Lines: 28 Message-ID: Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit X-Trace: news.uni-berlin.de TdTDvnwECfeAsbrVm8DVgA+tZuLfMYxKNhNAKz0cnM7g== Return-Path: X-Original-To: python-list@python.org Delivered-To: python-list@mail.python.org X-Spam-Status: OK 0.005 X-Spam-Evidence: '*H*': 0.99; '*S*': 0.00; 'python,': 0.02; 'puts': 0.07; 'ruby,': 0.09; 'subject:Why': 0.09; 'python.': 0.11; 'def': 0.13; 'lambda': 0.16; 'received:io': 0.16; 'received:psf.io': 0.16; 'subject:default': 0.16; 'language': 0.19; 'this:': 0.23; 'header:User-Agent:1': 0.26; "doesn't": 0.26; 'message- id:@gmail.com': 0.34; 'received:google.com': 0.35; 'received:74.125.82': 0.35; 'needed': 0.36; 'to:addr:python-list': 0.36; 'subject:?': 0.36; 'end': 0.39; 'why': 0.39; 'received:192': 0.39; 'to:addr:python.org': 0.40; 'why?': 0.91; 'received:192.168.0.4': 0.93 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=message-id:date:from:user-agent:mime-version:to:subject :content-transfer-encoding; bh=GFBvHAe1U9aEXSqJwPh8RopUyBcvvbjgHYf6iFXeYxI=; b=kLpxhcstx0PA9nW9auGKwv/+e+csVTu7BipvqNaapob3f4qjmLMj7eJBaHagd7KvnJ 9NMo98XXOOpZCyNrFFt+irYpN7osOPZv0JM3mT8UjoYbixGN6HS7yze9Uv99FBD6VE9M vfkMkFQGJhCURXm9XRcYOhfE6XN6g+80BhNwCoVVulh0PtB0/dm2/JZXRaKpC58GXqO3 YxnM176fIvtJz0VVcgMhxUf9uagZfRB8rgFG7XmrIiWn/SYZFWxuQaNlkfWmFV0fZObf Dk2BVXvPLvC9apN6rt0r3Ib2IQJsIwxVmVy3wrVgkfgQk0Ue6rollw1rytQHONTsWSGb zznQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:message-id:date:from:user-agent:mime-version:to :subject:content-transfer-encoding; bh=GFBvHAe1U9aEXSqJwPh8RopUyBcvvbjgHYf6iFXeYxI=; b=IBjrejl4SHETTAQzYSko0tSF3UOwLbd5HAYhc7sQOFLTL+xgqWaoooi+zxjHC+ePYD GfiaWbK9kPr4vqbEviEN28mzXW6+nNulKE6qZD2UJ6SWotjW+JmNpH7lqDPYGB9obMqL d/0N6IzO7oJ4W9f6LFMUkII5E3+wJkWbi/b6OXJpO3YqqQGSdayxVT/DbfD9uJcNKapw Iy5zcccOI/Pgkz6UmeT5fdnq5cwxcMhrwemWJ/9oEux8c7JcZ/+9KJrWc3tULWQUugMs hgalw3rAhdyaST5y8rikBIX6uuKkK6n50xom4Pebcv+yfU6Lwt/iirMPfPFic0MTJ1+F mhWQ== X-Gm-Message-State: AD7BkJLWQl6Lpvpfulj3vjdZhc9zeT7C98s6zm/N0qbVd/94Mvh/mP2lPZteqR1qFFn0gA== X-Received: by 10.194.89.70 with SMTP id bm6mr24935639wjb.0.1459043169722; Sat, 26 Mar 2016 18:46:09 -0700 (PDT) User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.10; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 X-Mailman-Approved-At: Sun, 27 Mar 2016 09:55:01 -0400 X-BeenThere: python-list@python.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: General discussion list for the Python programming language List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Xref: csiph.com comp.lang.python:105840 Given that Python, like Ruby, is an object-oriented language why doesn't this: def m(): a = [] for i in range(3): a.append(lambda: i) return a b = m() for n in range(3): print(b[n]()) # => 2 2 2 ... work the same as this in Ruby: def m a = [] (0..2).each {|i| a << ->(){i}} a end aa = m (0..2).each {|n| puts aa[n].()} # => 0 1 2 lambda i=i: i ... is needed to make it work in Python. Just wondered why? gvim