Searching for ID from big lists faster in python 2.7?

Question

So I have these two lists:

image_names = ["IMG_1.jpg", "IMG_2.jpg"]
data = [{"name": "IMG_1.jpg", "id": "53567"},
        {"name": "IMG_2.jpg", "id": "53568"},
        {"name": "IMG_3.jpg", "id": "53569"},
        {"name": "IMG_4.jpg", "id": "53570"}]

I want to search for the first item then the next one and so on in images_names in data and if it has the same name to get the id and add it to a list.

This is how I'm doing this:

for image_name in image_names:
    for datum in data:
        datum_name = datum.get("name", None)
        if datum_name == image_name:
           images_ids.append(datum.get("id", None))

Right now it works great but I think this is really inefficient once I get a lot of data in images_names and data. What's the best way in Python to do this? I'm using python 2.7

Answer 1

The main problem is that your data structure isn't set up to give you the access you want. Instead of a list of dicts, make this the natural dict that you want to use:

data = {"IMG_1.jpg": "53567",
        "IMG_2.jpg": "53568",
        "IMG_3.jpg": "53569",
        "IMG_4.jpg": "53570"}

Now, all you need to make the list of corresponding ids is

images_ids = [data[img] for img in image_names]

If you have a need for both methods of access (if you still need the name and id labels), then I recommend that you learn to use a Pandas data frame, with name and id as the columns. This will give you the best of both methods.