（Python）拆分字符串多個分隔符更有效？1) 使用多重替換方法然後使用拆分 2) 使用正則表達式 ((Python) which is more efficient to split a string multiple separators? 1) Using multiple replace method then using split 2) using regular Expressions)

問題描述

（Python）拆分字符串多個分隔符更有效？1) 使用多重替換方法然後使用拆分 2) 使用正則表達式 ((Python) which is more efficient to split a string multiple separators? 1) Using multiple replace method then using split 2) using regular Expressions)

示例：

（案例1）

#先用replace方法將不同類型的分隔符替換為單一類型，然後再用split方法

text = "python is, an easy;language; to, learn."
text_one_delimiter = text.replace("# ", ", ").replace("% ", ", ").replace("; ", ", ").replace("‑ ", ", ")

print(text_one_delimiter.split(", "))

(case 2)

#使用正則表達式進行分割使用多個分隔符

import re

text = "python is# an% easy;language‑ to, learn."
print(re.split('; |, |# |% |‑ ', text))

參考解法

方法 1:

timeit module is useful for speed comparison of code snippet. It might be used following way:

import timeit
case1 = '''text = "python is, an easy;language; to, learn."
text_one_delimiter = text.replace("# ", ", ").replace("% ", ", ").replace("; ", ", ").replace("‑ ", ", ")
text_one_delimiter.split(", ")'''
case2_setup = "import re"
case2 = '''text = "python is# an% easy;language‑ to, learn."
re.split('; |, |# |% |‑ ', text)'''
print(timeit.timeit(case1))
print(timeit.timeit(case2,case2_setup))

Output (will depend on your machine):

1.1250261999999793
2.2901268999999616

Note that I excluded prints from examined code and make import re setup, as otherwise it would import it without need several time. Conclusion is that in this particular case method with multiple .replaces is faster than re.split.

(tested in Python 3.7.3)

(by Shambhav Agrawal、Daweo)

參考文件

1. (Python) which is more efficient to split a string multiple separators? 1) Using multiple replace method then using split 2) using regular Expressions (CC BY‑SA 2.5/3.0/4.0)