With npm, as simple as:
npx kill-port 5678
Author Archives: lucia
SQLAlchemy: Difference between Flush and Commit
In simple terms:
- Similarity: after both
flushandcommit, later queries will be able to retrieve these changes. - Difference:
flush()changes are in a pending state (no db statements are issued yet), and can be undone byrollback(); commits are persisted to db and non-reversible.
Why use flush:
- To have atomicity–making sure that a group of transactions either all succeed or all fail.
Expected — Waiting for status to be reported
Github actions getting stuck in limbo, never starting. No fear! There is a solution!
Continue readingAn error has occurred: InvalidManifestError
Error running pre-commit:
Type tag 'jupyter' is not recognized. Try upgrading identify and pre-commit?Python Function Fun Facts
A string identifier is attached to every function at creation time
- Which is nice for debug:
>>> dance.__name__
'dance'Functions capture local state
- Just like JavaScript, (lexical) closure:
- A closure remembers the values from its enclosing scope when it was created
To check whether something is callable
- Objects can be made callable, by being assigned function as value
- So, to check whether an object is callable:
>>> callable(foo)
True/FalseBenefit of functions being first class
- We are able to abstract and pass around behaviours
How to Reset Docker Container DB
Sometimes data is corrupted, and you just want to nuke the whole world and start a new life. In which case do:
$ docker container prune
$ docker volume pruneDomain Driven Design in Python 101
Domain Driven Design basically means to let business logic decide on object model, and construct the rest of the code from that starting point. Instead of, say, starting off by designing db schema and build from grounds up.
Continue readingWhy Use Assertion
And, what is the difference between raising normal errors and assertions? Basically:
| Raising Error | Assertion |
Raise ValueError('Input not in range [1, 10]') | assert 1 <= v <= 10 |
| Intended for users | Intended for developers |
| Happens when user action is illegal | Happens when code contains bug |
| To signal to user to take a different course of action | To easily find where code starts to error |
| Cannot and should not be disabled | Can be disabled during compilation, therefore should not be used in logics like data validation |
AttributeError: module ‘selectors’ has no attribute ‘SelectSelector’
Usually, the error module x has no attribute y means that:
- Your working directory contains a
xfile, which collides with python’sxmodule - You are running a python script from a directory (thereby making it your current working directory) where file
xcollides with python’sxmodule