item_1 = foo
list_1 = []
list_2 = []
list_3 = []
Is it possible to append item_1 to list_1, list_2 and list_3 in one line?
list_1.append(item_1)
list_2.append(item_1)
list_3.append(item_1)
seems very lousy to me; I have nearly 20 lists and I need one item in all of them.
Use loops:
lists_to_append_to = [list1,list2]
for list in lists_to_append_to:
list.append(item_1)
if the names of the lists are really list_1,2 etc you should probably should a dictionary though:
lists = {
1: list(),
2: list()
}
In that case use the dictionary in the loop.
for current_list in lists:
lists[current_list].append(item)
list is a terrible variable name as it shadows the built-in type.
We can create a list of lists and use a for loop to iterate over all of them.
item_1 = 'foo'
list_1 = []
list_2 = []
list_3 = []
Here we create a list of lists (it can be any length):
mylist = [list_1, list_2, list_3]
Next we iterate over all the lists in the main list, one by one.
Each list will be referenced by the target variable (in this case "l") and we can then call .append() on l.
for l in mylist:
l.append(item_1)
To prove this works, we can then examine the main list and individual lists:
print(mylist)
[['foo'], ['foo'], ['foo']]
print(list_1)
['foo']
print(list_2)
['foo']
x_1, x_2, ...of similar type and purpose, you should consider putting them in a list or other collection that allows dealing with them in bulk.y = lambda x: (list_1.append(x), list_2.append(x), list_2.append(x)) y(item_1)