Python中p5库运行报错：AttributeError: module '__main__' has no attribute 'preload'

问题重现 #

运行以下代码时触发错误：

from p5 import setup, draw, size, background, run
import numpy as np


width = 500
height = 500

def setup():
    size(width, height)


def draw():
    background(51)

run()

错误输出：

Traceback (most recent call last):
  File "c:/Users/Admin/main.py", line 15, in <module>
    run()
  File "C:\Users\Admin\AppData\Local\Programs\Python\Python38\lib\site-packages\p5\sketch\userspace.py", line 160, in run
    preload_method = __main__.preload
AttributeError: module '__main__' has no attribute 'preload'

解决方法 #

这个错误的核心原因是：p5库的run()函数默认会尝试从主模块中查找preload预加载函数，哪怕你根本不需要用到预加载逻辑。有两种简单的修复方式：

方式1：添加空的preload函数 #

直接在代码里定义一个空的preload函数，满足库的查找要求即可：

from p5 import setup, draw, size, background, run
import numpy as np


width = 500
height = 500

def preload():
    # 空函数，无需编写任何逻辑
    pass

def setup():
    size(width, height)


def draw():
    background(51)

run()

方式2：修改run()参数，禁用preload检查 #

调用run()时传入preload=False，明确告诉库不需要加载预加载函数：

from p5 import setup, draw, size, background, run
import numpy as np


width = 500
height = 500

def setup():
    size(width, height)


def draw():
    background(51)

run(preload=False)  # 添加该参数跳过preload检查

内容的提问来源于stack exchange，提问作者Mody