从字符串中提取定量信息

Question

我正在分析 Open Food Facts 数据集。数据集非常混乱，有一个名为 'quantity' 的列，其中包含如下条目：

'100克',
'5 盎司（142 克）'，
'12 盎司',
'200克',
'12 盎司（340 克）'，
'10 盎司（296 毫升）',
'750 毫升',
'1l',
'250 毫升', '8 盎司',
'10.5 盎司（750 克）'，
'1 加仑（3.78 升）',
'27 盎司（1 磅 11 盎司）765 克',
'75 cl',

如您所见，到处都是数值和度量单位！有时数量以两种不同的测量方式给出...... 我的目标是在我的 pandas 数据框中创建一个新列 'quantity_in_g'，我从字符串中提取信息并根据 'quantity' 列中的克数创建一个整数值. 因此，如果数量列为“200 g”，我想要整数 200，如果它显示“1 kg”，我想要整数 1000。我还想将其他测量单位转换为克。对于“2 oz”，我想要整数 56，对于 1 L，我想要 1000。
有人可以帮我转换这个专栏吗？非常感谢！
提前致谢

Answer 1

raw_data_lst = ['100 g ','5 oz (142 g)','12 oz','200 g ','12 oz (340 g)','10 f oz (296ml)','750 ml','1 l','250 ml', '8 OZ',] 
# 10 f oz (296ml)  don't know what f is
# if more there is more data like this then gram_conv_dict.keys() loop over this instead of directly ... doing what i have done below

in_grams_colm = []
gram_conv_dict ={
    'g':1,
    'oz': 28.3495,
    'kg':1000,
    'l': 1000 # assuming 1 litre of water --> grams
    }
# ml --> g is tricky as density varies

def convert2num(string_num):
    try:
        return int(string_num)
    except ValueError:
        return float(string_num)

def get_in_grams(unit):
    try:
        return gram_conv_dict[unit.lower()]
    except:
        print('don\'t know how much grams is present in 1',unit+'.')

    return 1


for data in raw_data_lst:
    i = 0
    quantity_str =''
    quantity_num = 0
    while i < len(data):
        if  47 < ord(data[i]) < 58 or data[i] == '.':
            quantity_str+= data[i]
        else:
            # data[i] = '' most abbrv has at most length = 2 therefore data[i+1:i+3] or u can just send the whole data[i+1:]
            # gram_conv_dict[data[i+1:i+3].strip()] directly check if key exist
            break

        i+=1

    quantity_num = convert2num(quantity_str)*get_in_grams(data[i+1:i+3].strip()) # assuming each data has this format numberspace-- len 2 abbrv
    in_grams_colm.append(quantity_num) # if u want only integer int(quantity_num)

#print(in_grams_colm)

def nice_print():
    for _ in in_grams_colm:
        print('{:.2f}'.format(_))

nice_print()
'''
output

don't know how much grams is present in 1 f.
don't know how much grams is present in 1 ml.
don't know how much grams is present in 1 ml.
100.00
141.75
340.19
200.00
340.19
10.00
750.00
1000.00
250.00
226.80'''

从字符串中提取定量信息

Extracting quantitative Information out of Strings

python

regex

pandas

feature-extraction

text-extraction