Python中基于名称合并两个嵌套列表的技术求助

Hey there! Since you're new to Python, let's break this down in a straightforward way. The core idea here is to make name lookups quick and easy using a dictionary, then combine entries where names match. Let's dive in:

First, let's fix a small syntax detail from your original code—text values like names and dates need to be wrapped in quotes in Python, otherwise the interpreter will treat them as undefined variables:

FirstList = [['joe', '12-mar', 2101], ['mike', '13-mar', 2102], ['mario', '15-mar', 2103]]
SecondList = [[2524, 'joe'], [2786, 'mike']]

Step 1: Create a Name-to-Number Mapping #

We'll convert SecondList into a dictionary where each key is a name, and the value is the corresponding number. This lets us check if a name exists in SecondList in a single, fast step:

# Build a dictionary to map names from SecondList to their numbers
name_number_map = {item[1]: item[0] for item in SecondList}

Step 2: Merge Matching Entries #

Now we loop through each entry in FirstList, check if the name is present in our dictionary, and if so, combine the entry with the matching number:

result = []
for entry in FirstList:
    name = entry[0]
    if name in name_number_map:
        # Append the number from the dictionary to the original entry
        merged_entry = entry + [name_number_map[name]]
        result.append(merged_entry)

print(result)

Shorter Version with List Comprehension #

Once you get comfortable with list comprehensions (a handy Python shortcut), you can write this in one line:

result = [entry + [name_number_map[entry[0]]] for entry in FirstList if entry[0] in name_number_map]

Output #

Both approaches will produce your desired result:

[['joe', '12-mar', 2101, 2524], ['mike', '13-mar', 2102, 2786]]

This method is efficient and easy to follow—perfect for someone getting started with Python. If you have questions about any part, feel free to ask!

内容的提问来源于stack exchange，提问作者Djordje pantovic