Question

Ex. Lets consider, I have a list,

list_var = ['sales_qty' , 'returns_qty' , 'net_sales_qty' , 'sales_amt' , 'returns_amt' ,'product_discount_amt' , 'product_net_amt' ,'product_cost_amt' , 'gross_sales_amt' , 'supplier_disc_amt' , 'category_disc_amt' , 'topup_disc_amt' , 'value_at_cost']

from this list element, i want to init these elements as list in the memory, so i could use append, extend method for these elements.

As follow,

#Need these variable in memory..
sales_qty = [], returns_qty  = [], net_sales_qty = [] ... value_at_cost = []

#list operation on variable..
sales_qty.append(5)

Is there any simple way to do that, so i could remove element or add element in list easily?

Answer 1

You could create a dictionary of lists based on list_var .

list_var = ['sales_qty' , 'returns_qty' , 'net_sales_qty' , 'sales_amt' , 'returns_amt' ,'product_discount_amt' , 'product_net_amt' ,'product_cost_amt' , 'gross_sales_amt' , 'supplier_disc_amt' , 'category_disc_amt' , 'topup_disc_amt' , 'value_at_cost']

list_dic = {k: [] for k in list_var}

Now can access your lists through the list_dic dict:

list_dic['sales_qty'].append(123)
list_dic['category_disc_amt'].append('abc')

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If you’re using a python version that does not support dict comprehensions (python 2.6 or lower), you can use a list comprehension instead (as DSM explained in his comment):

list_dic = dict((k, []) for k in list_var)