如何在嵌套列表（list of lists）中筛选出ID以指定前缀开头的子列表

Hey there! Let's solve this problem where we need to filter a nested list to return only the rows whose ID starts with a specific prefix.

First, let's recap our input data:

list_of_lists = [
    ['ID', 'Last', 'First', 'GradYear', 'GradTerm', 'DegreeProgram'],
    ['101010', 'Lee', 'Shane', '2019', 'Spring', 'MSA'],
    ['101020', 'Zhang', 'Eve', '2019', 'Summer', 'MSSD'],
    ['101030', 'Anthony', 'Daisy', '2020', 'Fall', 'MSBA']
]

Approach #

The core idea here is straightforward:

• Keep the header row intact (since it doesn't contain an ID value)
• Iterate through the data rows and check if the first element (the ID) starts with our target prefix
• Combine the header with all matching data rows to preserve the original list structure

Solution Code #

Here's a clean, reusable function to handle this:

def filter_by_id_prefix(data, prefix):
    # Grab the header row (first element of the nested list)
    header = data[0]
    # Use a list comprehension to filter rows where ID starts with the prefix
    filtered_data = [row for row in data[1:] if row[0].startswith(prefix)]
    # Return the header plus filtered rows to maintain consistency with input format
    return [header] + filtered_data

# Example usage: Filter for IDs starting with "10"
filtered_result = filter_by_id_prefix(list_of_lists, "10")

# Print the result to verify
for row in filtered_result:
    print(row)

How It Works #

• row[0] targets the ID column directly (since each sublist's first element is the ID)
• str.startswith(prefix) is ideal here—it efficiently checks if the ID string begins with our specified prefix, which aligns perfectly with the requirement
• We separate the header from data rows upfront to avoid accidentally filtering out column names

Test Cases to Try #

• Pass "10101" as the prefix, and you'll only get the row with ID 101010
• Use a non-matching prefix like "99", and the result will just be the header row
• An empty prefix ("") will return all rows, since every string starts with an empty string

内容的提问来源于stack exchange，提问作者Hongteng Wang