Google Colab中导入etldr包时遭遇Syntax Error问题求助

Hey there, let's break down exactly what's going on here and how to fix it:

The syntax error you're hitting comes down to one key detail: the etldr package uses the walrus operator (:=), a feature that was only added in Python 3.8. But Google Colab's default environment for Python 3.7 doesn't support this syntax—hence why your local setup (likely running Python 3.8+) worked fine, but Colab is throwing an error.

Here are three straightforward ways to get your ETL Character Database loading back on track:

Option 1: Upgrade Python in Colab to 3.8+ #

The cleanest fix is to switch Colab to a newer Python version that supports the walrus operator. Run these commands in a code cell first:

!sudo apt-get update -y
!sudo apt-get install python3.8
!sudo update-alternatives --install /usr/bin/python3 python3 /usr/bin/python3.7 1
!sudo update-alternatives --install /usr/bin/python3 python3 /usr/bin/python3.8 2
!sudo update-alternatives --config python3
# Install pip for the updated Python version
!curl https://bootstrap.pypa.io/get-pip.py | python3.8

After running this, restart your Colab runtime (go to Runtime > Restart runtime), then reinstall the etldr package:

!pip install etldr

Your import statements should now work without any syntax issues.

Option 2: Patch the etldr source file manually #

If upgrading Python feels like overkill, you can edit the problematic line directly in the package's source code:

1. The file path you already found is: /usr/local/lib/python3.7/dist-packages/etldr/etl_data_reader.py
2. Open the file (you can use !nano /usr/local/lib/python3.7/dist-packages/etldr/etl_data_reader.py in a code cell) and replace this line:

   while(_bytes := f.read(data_info.struct_size)):
   

   With this Python 3.7-compatible equivalent:

   _bytes = f.read(data_info.struct_size)
   while _bytes:
       # Keep all the existing loop code here unchanged
       # Add this line at the end of the loop to refresh the value
       _bytes = f.read(data_info.struct_size)
   

Save the file, and your imports should start working.

Option 3: Use a Python 3.7-compatible fork of etldr #

If you can find a community-maintained fork of the etldr package that removes the walrus operator for older Python versions, install that instead of the official package. For example (replace the URL with a real compatible fork if you locate one):

!pip install git+https://github.com/[username]/etldr-py37-compatible.git

Any of these methods will resolve the syntax error and let you get back to training your kanji recognition neural network with the ETL dataset.

内容的提问来源于stack exchange，提问作者Kujinn