Question

我有一个我想在pandas数据帧中搜索的单位列表，然后将这些单位转换为正确命名的单位，并将它们的值乘以下面列表中的常数因子。这是示例数据框

>> df
product                     info
product___A     3.5 m mini-jack
product___B     3.5 kg mini-jack
product___C     3.5mm mini-jack
product___D     3.5 millimeter mini-jack
product___E     43 centimeter mini-jack

这是我的代码实现

import re
import pandas as pd
units_origianal = ['Kilogram', 'millimeter', 'pounds', 'ounce', 'centimeter', 'kilometers']
units = ['kg', 'mm', 'lbs' 'oz', 'cm', 'm']
factor = [0.543, 654.53, 53.64,0.744, 43.8, 98.123]
def norm_units(x):
    for i in range(len(units)):
        if ('\d+\s'+units_origianal[i] in x or re.search('\d+'+units_origianal[i],str(x))):
            quantity = re.findall("\d+\.\d+", str(x))[0]
            resulting_quantity = float(quantity) * factor[i]
                return x.replace(quantity, resulting_quantity).replace(units_origianal[i], units[i])

df = df.apply(norm_units)


>> df
    # Expected resulting Dataframe
product                     info
product___A      344.05 m mini-jack
product___B      1.9005 kg mini-jack
product___C      2290.155 mm mini-jack
product___D      2290.155 mm mini-jack
product___E      1883.4 cm mini-jack

运行代码后得到的结果数据框

  product info
0  None  None
1  None  None
2  None  None
3  None  None
4  None  None

赞赏并提前感谢您的帮助。

Answer 1

您可能希望将str.replace与正则表达式组

一起使用

>> factors = {'Kilogram': 0.543, 'kg': 0.543, 
              'millimeter': 654.54, 'mm': 654.54,
              'pounds': 53.64, 'lbs': 53.64,
              'ounce': 0.744, 'oz': 0.744,
              'centimeter': 43.8, 'cm': 43.8, 
              'kilometers': 98.123, 'm': 98.123}
>> pat = "(?P<val>\d+\.?\d?)\s*(?P<unit>(%s))" % '|'.join(factors)
>> def repl(p):
>>     val, unit = float(p.group('val')), p.group('unit')
>>     return str(factors[unit] * val) + ' ' + unit
>> df['info'] = df['info'].str.replace(pat, repl)
>> df

    product      info
0   product___A  343.4305 m mini-jack
1   product___B  1.9005 kg mini-jack
2   product___C  2290.89 mm mini-jack
3   product___D  2290.89 millimeter mini-jack
4   product___E  1883.3999999999999 centimeter mini-jack

在pandas dataframe python的循环中为每次迭代使用不同的正则表达式

1 个答案: