(base) F:>pip3 install nltk 'pip3' 不是内部或外部命令，也不是可运行的程序或批处理文件。
我该怎么做才能解决这个问题。提前致谢
(base) F:\>conda install -c anaconda nltk
WARNING: The conda.compat module is deprecated and will be removed in a future release.
Collecting package metadata: done
Solving environment: done
==> WARNING: A newer version of conda exists. <==
current version: 4.6.11
latest version: 4.6.14
Please update conda by running
$ conda update -n base -c defaults conda
## Package Plan ##
environment location: F:\Python
added / updated specs:
- nltk
......................................................
......................................................
Executing transaction: \ WARNING conda.gateways.disk.delete:unlink_or_rename_to_trash(138): Could not remove or rename …