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Date: Thu, 10 Apr 2014 21:54:40 +0800
Subject: why i have the output of [None, None, None]
From: length power <elearn2014@gmail.com>
To: python-list@python.org
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>>> x=['','x1','x2','x3','   ']
>>> x
['', 'x1', 'x2', 'x3', '   ']
>>> [print("ok") for it in x if it.strip() !=""]
ok
ok
ok
[None, None, None]

i understand there are three 'ok' in the output,but why i have the output
of [None, None, None]

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<div dir=3D"ltr"><div>&gt;&gt;&gt; x=3D[&#39;&#39;,&#39;x1&#39;,&#39;x2&#39=
;,&#39;x3&#39;,&#39;=A0=A0 &#39;]<br>&gt;&gt;&gt; x<br>[&#39;&#39;, &#39;x1=
&#39;, &#39;x2&#39;, &#39;x3&#39;, &#39;=A0=A0 &#39;]<br>&gt;&gt;&gt; [prin=
t(&quot;ok&quot;) for it in x if it.strip() !=3D&quot;&quot;]<br>
ok<br>ok<br>ok<br>[None, None, None]<br><br></div>i understand there are th=
ree &#39;ok&#39; in the output,but why i have the output of [None, None, No=
ne]<br></div>

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