How to remove specific characters from the beginning of a string

Question

I have a DataFrame which has a column named AlternateName. This contains names of different ingredients, but most of them have amounts and units before the actual name.

                                     Alternate_Name
2                                   ★ Sukkerfri chokolade
3                     100 g. sukkerfri 70% mørk chokolade
4                                     sukkerfri chokolade
5                      50 g. sukkerfri 70% mørk chokolade
6                        Chokoladesovs uden tilsat sukker
7                          1 spsk Chokolade proteinpulver
8                        1 spsk proteinpulver (chokolade)
9                        1,5 spsk chokolade proteinpulver
10                           spsk chokolade proteinpulver
11                      stor spsk chokolade proteinpulver
12                            30 g chokoladeproteinpulver
13                 30 g Linus Pro proteinpulver med Kakao
14            30 g proteinpulver med Kakao fra Linus Pro*
15      45 g proteinpulver (jeg brugte chokolade/hasse...
16            50 g chokolade og banan proteinpulver (HER)
17                           ,5 spsk vanilleproteinpulver
18                    1 spsk proteinpulver – Vanille smag
19                           1 spsk vanille proteinpulver
20                          1 spsk vanille proteinpulver
21                      1 stor spsk vanille proteinpulver
22                             10 g vanille proteinpulver
23                            spsk vanilje protein pulver
24                            spsk Vanille Protein pulver
25                             spsk Vanille proteinpulver
26      spsk vanilleproteinpulver (eller lidt vanilles...
27               30 g Linus Pro Proteinpulver med vanille
28      30 g vanille proteinpulver fra Linus Pro   (Re...
29                            30 g vanille proteinpulver
30                              40 g vanilleproteinpulver
31                             60 g vanille proteinpulver

I already tried this: df = df["AlternateName"].map(lambda x: x.lstrip('200 g.')) - however, I need to add specific conditions on which these strings shall be trimmed as I can not do that manually for each and every situation.

Therefore, how can I teach my program to remove string contents using conditions to match numbers, units and special characters situated before every ingredient name?

ex: 200 g. sukkerfri chokolade -> sukkerfri chokolade

★ Sukkerfri chokolade -> Sukkerfri chokolade

I am not quite familiar with python, so any help like methods, tips, hints, are welcome!

Answer 1

Have you already tried to apply a regex to remove the quantities? Like this:

df['Alternate_Name'].str.replace(r'^\s*(★|[0-9]*,?[0-9]{1,}\s*(g|kg|spsk|stor spsk)|spsk)\s*,*', '')

It outputs:

Out[71]: 
0                            ★ Sukkerfri chokolade
1                   . sukkerfri 70% mørk chokolade
2                              sukkerfri chokolade
3                   . sukkerfri 70% mørk chokolade
4                 Chokoladesovs uden tilsat sukker
5                          Chokolade proteinpulver
6                        proteinpulver (chokolade)
7                          chokolade proteinpulver
8                          chokolade proteinpulver
9                stor spsk chokolade proteinpulver
10                          chokoladeproteinpulver
11               Linus Pro proteinpulver med Kakao
12          proteinpulver med Kakao fra Linus Pro*
13    proteinpulver (jeg brugte chokolade/hasse...
14          chokolade og banan proteinpulver (HER)
15                            vanilleproteinpulver
16                    proteinpulver – Vanille smag
17                           vanille proteinpulver
18                           vanille proteinpulver
19                           vanille proteinpulver
20                           vanille proteinpulver
21                          vanilje protein pulver
22                          Vanille Protein pulver
23                           Vanille proteinpulver
24    vanilleproteinpulver (eller lidt vanilles...
25             Linus Pro Proteinpulver med vanille
26    vanille proteinpulver fra Linus Pro   (Re...
27                           vanille proteinpulver
28                            vanilleproteinpulver
29                           vanille proteinpulver
Name: Alternate_Name, dtype: object