get substring Python inside list elements- Web Scraping

One option (according to the data samples that you provided) can be this:

import re
strings = ['Fresh Value Colocasia 250g', 'Fresh Value Banana Robusta 1kg', 'Fresh Value Raw Papaya 1 U (units) (300g-400g)','Fresh Value Premium Pomegranate Kabul (500g - 700g)']
for i in strings:
    start = re.findall('\d|\(', i)[0]
    name = i.split(start)[0].strip()
    quantity = start + i.split(start)[1]
    print 'Name = '+ name + ', Quantity = ', quantity

Output:

Name = Fresh Value Colocasia, Quantity =  250g
Name = Fresh Value Banana Robusta, Quantity =  1kg
Name = Fresh Value Raw Papaya, Quantity =  1 U (units) (300g-400g)
Name = Fresh Value Premium Pomegranate Kabul, Quantity =  (500g - 700g)

Of course it is valid if the numbers and parenthesis are present only in the quantity and not in the name. If the quantity starts with other symbols, you can add them in findall

import re
def substring(string):
    output = {}
    name = string.split()[0]
    for i in range(1,len(string.split())):
        if len(re.findall('\d', string.split()[i]))==0:
            name = name + " " + string.split()[i]
        else:
            quantity = " ".join(string.split()[i:])
            break
    output["Name"] = name
    output["Quantity"] = quantity
    return output

Then put strings into this function like:

substring("Fresh Value Raw Papaya 1 U (units) (300g-400g)")

And you will get:

{'Name': 'Fresh Value Raw Papaya', 'Quantity': '1 U (units) (300g-400g)'}

you can also try this:

def split_unit(stri):
    to_split = re.findall("\\d+",stri)[0]
    splitted = to_split + stri.split(to_split,1)[1]
    print(splitted)

split_unit("Fresh Value Colocasia 250g") #outputs : 250 g
split_unit("Fresh Value Banana Robusta 1kg") #outputs : 1Kg
split_unit("Fresh Value Raw Papaya 1 U (units) (300g-400g)") # outputs:1 U 
                                     #(units) (300g-400g) 

And so on, What I've done is, first find the first occurrence of a intiger in your string by using regex in the first line inside the function. And use str.split() method to split all the characters after the first integer and conctatinging it with the to_split which is the first integer.