加载MNIST数据集触发FileNotFoundError：文件或目录不存在

Hey there, let's work through this FileNotFoundError you're hitting when trying to load the MNIST dataset with mnist_loader.py. The error is clear: Python can't locate the ../data/mnist.pkl file, so we'll walk through the most common fixes below:

1. Verify the MNIST data file exists #

First, double-check if you actually have the mnist.pkl file in the expected location:

• Look for a data directory that's one level above where your mnist_loader.py is saved. If that directory doesn't exist, or it's missing mnist.pkl, you'll need to get the file first.
• The tutorial's official code repository includes this data file—you can locate the data folder in the repo and download mnist.pkl directly.

2. Correct the file path #

If you already have mnist.pkl but the path is misaligned, try these adjustments:

• Use an absolute path: Open mnist_loader.py and find the line where it loads mnist.pkl (usually in the load_data function). Replace the relative path ../data/mnist.pkl with the full absolute path to your file. For example:

  # Replace this line
  f = open('../data/mnist.pkl', 'rb')
  # With something like this (adjust to your actual file path)
  f = open('C:/Users/Joseph Gannon/data/mnist.pkl', 'rb')
  

• Fix the folder structure: Ensure your directory setup matches what the script expects. If mnist_loader.py is in C:/Users/Joseph Gannon/Projects/nn/, then ../data/mnist.pkl points to C:/Users/Joseph Gannon/data/mnist.pkl. Create that data folder in your user directory and place mnist.pkl inside it.

3. Check your working directory #

Sometimes the issue is that you're running the script from a different directory than where mnist_loader.py lives. To confirm, run this code before loading the data:

import os
print(os.getcwd())

This will show you your current working directory. Make sure the relative path ../data/mnist.pkl makes sense from this location. If not, either change your working directory to match the script's location, or adjust the path in mnist_loader.py.

4. Redownload the data (if corrupted or missing) #

If you suspect mnist.pkl is corrupted or you never downloaded it, grab a fresh copy from the tutorial's code repo. Some versions of mnist_loader.py include automatic download logic, but if yours doesn't, manually placing the file in the correct path will resolve the error.

内容的提问来源于stack exchange，提问作者Gonge