Is there an easier way to search for an pattern in a list of strings in python?

Question

I have a list of string and need a better wayt to search for patterns in that list. An exemple of list:

['red','green','red','red','red','red','green','red','red','green','green','red','green','green','red','red','green','green','green','green','green','green','green','red','red','red','red','red','red','green','red','red','red','red','red','red','red','green','green','red','red','green','red','green','green','green','green','green','red','red','green','green','green','red','green','red','green','red','red','green','green','red','green','green','red','red','green','green','red','red','green','green','green','green','red','red','red','red','red','green','green','green','green','red','green','red','green','red','green','red','red','green','red','green','red','green','red','red','red','red','green','red','red','red','green','green','green','red','red','green','green','red','green','red','green','red','green','green','green']

and patterns:

BLUE PATTERN:
['red','green','green','green']
['green','red','red','red']

PINK PATTERN:
['red','green','green','red']
['green','red','red','green']

The method needs to scan my list for patterns and generate another list with the names of the patterns in order that the patterns appeared for exemple:

['blue','pink','blue','blue',..]

That is what i have:

catalogacao = []

if len(self._items) < 4:
    return
for i, _ in enumerate(self._items):
    if i + 4 > len(self._items):
        break
    if self._items[i] == "red" and self._items[i+1] == "green" and self._items[i+2] == "green" and self._items[i+3] == "green":
        catalogacao.append("blue")

    if self._items[i] == "green" and self._items[i+1] == "red" and self._items[i+2] == "red" and self._items[i+3] == "red":
        catalogacao.append("blue")

    if self._items[i] == "red" and self._items[i+1] == "green" and self._items[i+2] == "green" and self._items[i+3] == "red":
        catalogacao.append("pink")

    if self._items[i] == "green" and self._items[i+1] == "red" and self._items[i+2] == "red" and self._items[i+3] == "green":
        catalogacao.append("pink")

Answer 1

You can iterate through your items, and for every sublist of 4 elements, check if the sublist equals a blue or a pink pattern

items = ['red','green','red','red','red','red','green','red','red','green','green','red','green','green','red','red','green','green','green','green','green','green','green','red','red','red','red','red','red','green','red','red','red','red','red','red','red','green','green','red','red','green','red','green','green','green','green','green','red','red','green','green','green','red','green','red','green','red','red','green','green','red','green','green','red','red','green','green','red','red','green','green','green','green','red','red','red','red','red','green','green','green','green','red','green','red','green','red','green','red','red','green','red','green','red','green','red','red','red','red','green','red','red','red','green','green','green','red','red','green','green','red','green','red','green','red','green','green','green']

blue_patterns = [['red','green','green','green'], ['green','red','red','red']]

pink_patterns = [['red','green','green','red'], ['green','red','red','green']]

catalogacao = []

#Iterate over the list
for idx in range(len(items)):

    #Check if the 4 element sublist match blue or pink pattern
    if any(item == items[idx:idx+4] for item in blue_patterns):
        catalogacao.append("blue")

    elif any(item == items[idx:idx+4] for item in pink_patterns):
        catalogacao.append('pink')

print(catalogacao)

The output will be

['blue', 'pink', 'pink', 'pink', 'pink', 'blue', 'blue', 'blue', 'pink', 
'pink', 'blue', 'pink', 'blue', 'pink', 'pink', 'pink', 'pink', 'pink', 
'pink', 'blue', 'blue', 'blue', 'pink', 'blue', 'blue', 'blue', 'pink', 
'pink', 'blue']