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    <p>Strings in Python are <em>immutable</em> (can't be changed). Because of this, the effect of <code>line.replace(...)</code> is just to create a new string, rather than changing the old one. You need to <em>rebind</em> (assign) it to <code>line</code> in order to have that variable take the new value, with those characters removed.</p> <p>Also, the way you are doing it is going to be kind of slow, relatively. It's also likely to be a bit confusing to experienced pythonators, who will see a doubly-nested structure and think for a moment that something more complicated is going on.</p> <p>Starting in Python 2.6 and newer Python 2.x versions *, you can instead use <a href="https://docs.python.org/2/library/stdtypes.html#str.translate" rel="noreferrer"><code>str.translate</code></a>, (but read on for Python 3 differences):</p> <pre><code>line = line.translate(None, '!@#$') </code></pre> <p>or regular expression replacement with <a href="https://docs.python.org/2/library/re.html#re.sub" rel="noreferrer"><code>re.sub</code></a></p> <pre><code>import re line = re.sub('[!@#$]', '', line) </code></pre> <p>The characters enclosed in brackets constitute a <em>character class</em>. Any characters in <code>line</code> which are in that class are replaced with the second parameter to <code>sub</code>: an empty string.</p> <p>In Python 3, strings are Unicode. You'll have to translate a little differently. kevpie mentions this in a <a href="https://stackoverflow.com/questions/3939361/remove-specific-characters-from-a-string-in-python#comment-4205256">comment</a> on one of the answers, and it's noted in the <a href="https://docs.python.org/2/library/stdtypes.html#str.translate" rel="noreferrer">documentation for <code>str.translate</code></a>.</p> <p>When calling the <code>translate</code> method of a Unicode string, you cannot pass the second parameter that we used above. You also can't pass <code>None</code> as the first parameter, or even a translation table from <code>string.maketrans</code>. Instead, you pass a dictionary as the only parameter. This dictionary maps the <em>ordinal values</em> of characters (i.e. the result of calling <a href="https://docs.python.org/2/library/functions.html#ord" rel="noreferrer"><code>ord</code></a> on them) to the ordinal values of the characters which should replace them, or—usefully to us—<code>None</code> to indicate that they should be deleted.</p> <p>So to do the above dance with a Unicode string you would call something like</p> <pre><code>translation_table = dict.fromkeys(map(ord, '!@#$'), None) unicode_line = unicode_line.translate(translation_table) </code></pre> <p>Here <a href="https://docs.python.org/2/library/stdtypes.html#dict.fromkeys" rel="noreferrer"><code>dict.fromkeys</code></a> and <a href="https://docs.python.org/2/library/functions.html#map" rel="noreferrer"><code>map</code></a> are used to succinctly generate a dictionary containing</p> <pre><code>{ord('!'): None, ord('@'): None, ...} </code></pre> <p>Even simpler, as <a href="https://stackoverflow.com/questions/23175809/typeerror-translate-takes-one-argument-2-given-python">another answer puts it</a>, create the dictionary in place:</p> <pre><code>unicode_line = unicode_line.translate({ord(c): None for c in '!@#$'}) </code></pre> <hr> <p>* for compatibility with earlier Pythons, you can create a "null" translation table to pass in place of <code>None</code>:</p> <pre><code>import string line = line.translate(string.maketrans('', ''), '!@#$') </code></pre> <p>Here <a href="https://docs.python.org/2/library/string.html#string.maketrans" rel="noreferrer"><code>string.maketrans</code></a> is used to create a <em>translation table</em>, which is just a string containing the characters with ordinal values 0 to 255.</p>
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    1. COIn Python3, `line.translate` takes only one argument and the first solution will not work
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    2. CO@marczoid: Thanks, added a note to that effect.
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