Python模糊匹配列表性能中的字符串
问题内容:
我正在检查在4个相同的数据框列中是否有相似的结果(模糊匹配),并且我以下面的代码为例。当我将其应用于实际的40.000行x
4列数据集时,将始终以整数运行。问题是代码太慢。例如,如果我将数据集限制为10个用户,则需要8分钟来计算,而要花20到19分钟。我有什么想念的吗?我不知道为什么要花这么长时间。我希望能在2小时或更短时间内获得所有结果。任何提示或帮助将不胜感激。
from fuzzywuzzy import process
dataframecolumn = ["apple","tb"]
compare = ["adfad","apple","asple","tab"]
Ratios = [process.extract(x,compare) for x in dataframecolumn]
result = list()
for ratio in Ratios:
for match in ratio:
if match[1] != 100:
result.append(match)
break
print (result)
输出:[(’asple’,80),(’tab’,80)]
问题答案:
编写矢量化操作并避免循环可显着提高速度
导入必要的包裹
from fuzzywuzzy import fuzz
import pandas as pd
import numpy as np
从第一个列表创建数据框
dataframecolumn = pd.DataFrame(["apple","tb"])
dataframecolumn.columns = ['Match']
从第二个列表创建数据框
compare = pd.DataFrame(["adfad","apple","asple","tab"])
compare.columns = ['compare']
合并-通过引入密钥(自加入)的笛卡尔积
dataframecolumn['Key'] = 1
compare['Key'] = 1
combined_dataframe = dataframecolumn.merge(compare,on="Key",how="left")
combined_dataframe = combined_dataframe[~(combined_dataframe.Match==combined_dataframe.compare)]
向量化
def partial_match(x,y):
return(fuzz.ratio(x,y))
partial_match_vector = np.vectorize(partial_match)
使用矢量化并通过在阈值上设置阈值来获得期望的结果
combined_dataframe['score']=partial_match_vector(combined_dataframe['Match'],combined_dataframe['compare'])
combined_dataframe = combined_dataframe[combined_dataframe.score>=80]
结果
+--------+-----+--------+------+
| Match | Key | compare | score
+--------+-----+--------+------+
| apple | 1 | asple | 80
| tb | 1 | tab | 80
+--------+-----+--------+------+