fdee957c34
* Modify rule S5361: Add Python as covered language * Fix typos in S5361 rule descriptions * Remove wrong delimiters * Rename var and fix comment
33 lines
1.1 KiB
Plaintext
33 lines
1.1 KiB
Plaintext
An `re.sub` call always performs an evaluation of the first argument as a regular expression, even if no regular expression features were used. This has a significant performance cost and therefore should be used with care.
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When `re.sub` is used, the first argument should be a real regular expression. If it's not the case, `str.replace` does exactly the same thing as `re.sub` without the performance drawback of the regex.
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This rule raises an issue for each `re.sub` used with a simple string as first argument which doesn't contains special regex character or pattern.
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== Noncompliant Code Example
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----
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input = "Bob is a Bird... Bob is a Plane... Bob is Superman!"
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changed = re.sub("Bob is", "It's", input) # Noncompliant
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changed = re.sub("\.\.\.", ";", changed) # Noncompliant
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----
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== Compliant Solution
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----
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input = "Bob is a Bird... Bob is a Plane... Bob is Superman!"
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changed = str.replace("Bob is", "It's", input)
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changed = str.replace("...", ";", changed)
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----
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Or, with a regex:
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----
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input = "Bob is a Bird... Bob is a Plane... Bob is Superman!"
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changed = re.sub(r"\w*\sis", "It's", input)
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changed = re.sub(r"\.{3}", ";", changed)
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----
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