Python僵尸集群统计代码报NameError: name 'zombie_array'未定义

Hey there, let's break down and fix this issue step by step!

What's Causing the Error? #

The NameError means you're trying to use a variable named zombie_array that hasn't been defined anywhere in your code. This almost always happens when you call the zombieCluster function with zombie_array as an argument, but you never created or assigned a value to that variable first.

On top of that, your zombieCluster function code is incomplete (the final line cuts off at for j in range(row)...), which would cause additional syntax or logic errors once you fix the variable issue.

Step-by-Step Fixes #

Let's address both problems with a complete, working version of your code:

1. Finish the zombieCluster function logic
   The goal of this function is to count connected zombie clusters using DFS. We need to check each zombie, and if they haven't been part of a scanned cluster yet, start a DFS and increment our count.

2. Define a valid input variable
   Before calling zombieCluster, make sure you've created a properly formatted zombie array (a list of strings where each string represents connections between zombies).

Complete Working Code #

#!/usr/bin/env python
def DFS(j, visited, zombies, row):
    for k in range(row):
        # Check if zombie j and k are connected, and we haven't marked this connection yet
        if zombies[j][k] == '1' and not visited[j][k]:
            # Mark both directions of the connection as visited
            visited[j][k] = True
            visited[k][j] = True
            DFS(k, visited, zombies, row)

def zombieCluster(zombies):
    row = len(zombies)
    # Edge case: empty input
    if row == 0:
        return 0
    count = 0
    # Initialize a 2D visited array to track checked connections
    visited = [[False for _ in range(row)] for _ in range(row)]
    
    for i in range(row):
        # Use the diagonal element to check if this zombie is part of an unscanned cluster
        if not visited[i][i]:
            count += 1
            DFS(i, visited, zombies, row)
    return count

# Example usage: Define your zombie array first, then call the function
if __name__ == "__main__":
    # Sample input: 4 zombies, 2 clusters (first 3 are connected, last is alone)
    my_zombies = [
        "1100",
        "1110",
        "0110",
        "0001"
    ]
    # Call the function with your defined variable (not the undefined zombie_array)
    cluster_count = zombieCluster(my_zombies)
    print(f"Total zombie clusters: {cluster_count}")

Key Improvements & Notes #

• Fixed DFS condition: Removed redundant checks for visited[k][j] since we mark both directions when we first detect a connection.
• Completed cluster counting logic: We use the diagonal entry visited[i][i] to check if a zombie hasn't been part of any scanned cluster yet—this avoids counting the same cluster multiple times.
• Valid input example: The my_zombies variable is properly defined before calling the function, so no more NameError.

If you were previously calling zombieCluster(zombie_array) elsewhere (like in a script or interactive shell), make sure you first define zombie_array with a valid value, e.g.:

zombie_array = ["101", "010", "101"]
print(zombieCluster(zombie_array))

内容的提问来源于stack exchange，提问作者Rowle