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POEfficient way to do a large number of search/replaces in Python?
 

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    <p>I'm fairly new to Python, and am writing a series of script to convert between some proprietary markup formats. I'm iterating line by line over files and then basically doing a large number (100-200) of substitutions that basically fall into 4 categories:</p> <pre><code>line = line.replace("-","&lt;EMDASH&gt;") # Replace single character with tag line = line.replace("&lt;\\@&gt;","@") # tag with single character line = line.replace("&lt;\\n&gt;","") # remove tag line = line.replace("\xe1","&amp;bull;") # replace non-ascii character with entity </code></pre> <p>the str.replace() function seems to be pretty efficient (fairly low in the numbers when I examine profiling output), but is there a better way to do this? I've seen the re.sub() method with a function as an argument, but am unsure if this would be better? I guess it depends on what kind of optimizations Python does internally. Thought I would ask for some advice before creating a large dict that might not be very helpful!</p> <p>Additionally I do some parsing of tags (that look somewhat like HTML, but are not HTML). I identify tags like this:</p> <pre><code>m = re.findall('(&lt;[^&gt;]+&gt;)',line) </code></pre> <p>And then do ~100 search/replaces (mostly removing matches) within the matched tags as well, e.g.:</p> <pre><code>m = re.findall('(&lt;[^&gt;]+&gt;)',line) for tag in m: tag_new = re.sub("\*t\([^\)]*\)","",tag) tag_new = re.sub("\*p\([^\)]*\)","",tag_new) # do many more searches... if tag != tag_new: line = line.replace(tag,tag_new,1) # potentially problematic </code></pre> <p>Any thoughts of efficiency here?</p> <p>Thanks!</p>
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