DEV Community: Lam Hoang

Store in Svelte

Lam Hoang — Tue, 18 Oct 2022 15:44:14 +0000

A store is simply an object with a subscribe method that allows interested parties to be notified whenever the store value changes:

<script>
  let countValue;
  const unsubscribe = count.subscribe(value => {
    count_value = value;
  });
  onDestroy(unsubscribe);
</script>

<h1>The count is {count_value}</h1>

Update the stored value:

<script>
  function increment() {
    count.update(n => n + 1)
  }
</script>

Set a value:

<script>
  function reset() {
    count.set(0);
  }
</script>

Usage
Use auto-subscription to get rid of subscribe and onDestroy methods:

<script>
  import { storeValue } from './AnotherComponent'
  // ...other imports come after
</script>

<h1>The count is {$storeValue}</h1>

Readable store

<script>
  export const time = readable(new Date(), function start(set) {
    // Implementation
    set()

    return function stop() {
      // Implementation
    }
  })
</script>

Writable store

<script>
  import { writable } from 'svelte/store';

  const count = writable(0, () => {
    console.log('got a subscriber');
    return () => console.log('no more subscribers');
  });
</script>

Derived store

…from another store.

<script>
  import { derived } from 'svelte/store';

  const delayed = derived(time, ($a, set) => {
    setTimeout(() => set($a), 1000);
  }, 'one moment...');

  // or (read-only derived):

  const elapsed = derived(time, $time =>
    Math.round(($time - start) / 1000)
  );

</script>

Custom store

// store.js

import { writable } from 'svelte/store';
function createCount() {
  const { subscribe, set, update } = writable(0);

  return {
    subscribe,
    increment: () => update(n => n + 1),
    decrement: () => update(n => n - 1),
    reset: () => set(0)
  };
}
export const count = createCount();

In the component:

<script>
  import { count } from './store.js';
</script>

<h1>The count is {$count}</h1>

<button on:click={count.increment}>+</button>
<button on:click={count.decrement}>-</button>
<button on:click={count.reset}>reset</button>

Handle Events in Svelte

Lam Hoang — Tue, 18 Oct 2022 15:39:45 +0000

<button on:click={handleClick}>
  Press me
</button>

<button on:click={() => console.log('I was pressed')}>
  Press me
</button>

<button on:click|once={handleClick}>
  Press me
</button>

<button on:submit|preventDefault={handleClick}>
  Press me
</button>

Svelte Cheat Sheet

Forwarding Events in Svelte

Lam Hoang — Tue, 18 Oct 2022 15:36:00 +0000

// Widget.svelte
<script>
  import { createEventDispatcher } from "svelte";
  const dispatch = createEventDispatcher();
</script>
<button on:click={() => dispatch('message', { text: 'Hello!' })} />
<button on:click>Press me</button>

// App.svelte
<script>
import Widget from '.Widget.svelte'
</script>

<Widget 
  on:click={() => alert('I was clicked')} 
  on:message={e => alert(e.detail.text)}>

Dplyr Make New Variables

Lam Hoang — Tue, 18 Oct 2022 15:18:17 +0000

Compute and append one or more new columns: dplyr::mutate(iris, sepal = Sepal.Length + Sepal. Width)
Apply window function to each column: dplyr::mutate_each(iris, funs(min_rank))
Compute one or more new columns. Drop original columns: dplyr::transmute(iris, sepal = Sepal.Length + Sepal. Width)
Copy with values shifed by 1: dplyr::lead
Copy with values lagged by 1: dplyr::lag
Ranks with no gaps: dplyr::dense_rank
Ranks. Ties get min rank: dplyr::min_rank
Ranks rescaled to [0, 1]: dplyr::percent_rank
Ranks. Ties got to first value: dplyr::row_number
Bin vector into n buckets: dplyr::ntile
Are values between a and b?: dplyr::between
Cumulative distribution: dplyr::cume_dist
Cumulative all: dplyr::cumall
Cumulative any: dplyr::cumany
Cumulative mean: dplyr::cummean
Cumulative sum: cumsum
Cumulative max: cummax
Cumulative min: cummin
Cumulative prod: cumprod
Element-wise max: pmax
Element-wise min: pmin

Dplyr Cheat Sheet

Creates an array of elements split into groups the length of size.

Lam Hoang — Tue, 18 Oct 2022 02:47:41 +0000

Creates an array of elements split into groups the length of size. If array can't be split evenly, the final chunk will be the remaining elements.

Arguments

array (Array): The array to process.
[size=1] (number): The length of each chunk

Returns

(Array): Returns the new array of chunks.

_.chunk(['a', 'b', 'c', 'd'], 2);
// => [['a', 'b'], ['c', 'd']]

_.chunk(['a', 'b', 'c', 'd'], 3);
// => [['a', 'b', 'c'], ['d']]

Lodash Cheat Sheet by simple cheat sheet

Lodash Debounce

Lam Hoang — Thu, 13 Oct 2022 08:03:12 +0000

The _.debounce() method of Function in lodash is used to create a debounced function that delays the given function until after the stated wait time in milliseconds has passed since the last time this debounced function was called. The debounced function has a cancel method that can be used to cancel the function calls that are delayed and a flush method that is used to immediately call the delayed function.

Syntax:

_.debounce( func, wait, options )

Parameters: This method accepts three parameters as mentioned above and described below:

func: It is the function that has to be debounced.
wait: It is the number of milliseconds for which the calls are to be delayed. It is an optional parameter. The default value is 0.
options: It is the options object that can be used for changing the behaviour of the method. It is an optional parameter.

The options object has the following parameters:

leading: It defines the calling on the leading edge of the timeout. It is an optional parameter. The default value is false.
maxWait: It is the maximum number of time for which the func is allowed to be delayed before it is called. It is an optional parameter.
trailing: It defines the calling on the trailing edge of the timeout. It is an optional parameter. The default value is true.

Conda Removing Packages or Environments

Lam Hoang — Mon, 10 Oct 2022 16:53:47 +0000

conda remove --name bunnies beautiful-soup Remove one package from any named environment

conda remove beautiful-soup Remove one package from the active environment

conda remove --name bunnies beautiful-soup astroid Remove multiple packages from any environment

conda remove --name snakes --all Remove an environment (remove all packages)

conda uninstall packagename Remove one package. Alias for conda remove

conda clean --all Delete unused packages and caches

Get full Conda Cheat Sheet

Conda Managing Packages, Including Python

Lam Hoang — Mon, 10 Oct 2022 16:53:10 +0000

conda list View list of packages and versions installed in active environment

conda list | grep pandas Search package in the list

conda list --show-channel-urls List all installed packages along its channels

conda list --export > env.txt Save to a Requirements file all packages in an environment

conda list > env.txt Save a package list an a file

conda search beautiful-soup Search for a package to see if it is available to conda install

conda search -c conda-forge black Search Alternate Channels specify different channels as well, with the use of the -c flag

conda search conda-forge::black Search Alternate Channels

conda install -n bunnies beautiful-soup Install a new package NOTE: If you do not include the name of the environment, it will install in the current active environment.

conda update beautiful-soup Update a package in the current environment

conda search --override-channels -c pandas bottleneck Search for a package in a specific location (the pandas channel on Anaconda.org)

conda install -c conda-forge black Installing black from the conda-forge channel

conda install -c pandas bottleneck Install a package from a specific channel

conda install scipy --channel conda-forge --channel bioconda Specifying multiple channels when installing a package

conda search --override-channels -c defaults beautiful-soup Search for a package to see if it is available from the Anaconda repository

conda install iopro accelerate Install commercial Continuum packages

conda install black isort flake8 install python linter

conda install conda-build Install conda-build

conda install matplotlib=1.4.3 Install a certain package version

conda install m2-patch posix Windows only

conda install --use-local click

conda skeleton pypi pyinstrument

conda build pyinstrument Build a package from a Python Package Index (PyPi) Package

Conda Cheat Sheet by simplecheatsheet.com

Managing .condarc Configuration

Lam Hoang — Mon, 10 Oct 2022 16:52:02 +0000

conda config --get Get all keys and values from my .condarc file

conda config --get channels Get value of the key channels from .condarc file

conda config --show channels Knowing the active channels

conda config --add channels pandas Add a new value to channels so conda looks for packages in this location

conda config --add channels defaults Adding a default channel

conda config --add channels conda-forge Adding a channel

conda config --add channels bioconda Adding a channel

conda config --set anaconda_upload yes Enable uploading to Anaconda Cloud

conda config --set anaconda_upload no Disable uploading to Anaconda Cloud

conda config --set auto_activate_base false Deactivating the activation of the base environment in Python

Conda Cheat Sheet by SimpleCheatSheet.com

Conda Managing Python

Lam Hoang — Mon, 10 Oct 2022 16:51:01 +0000

conda search --full-name python

conda search -f python Check versions of Python available to install

conda search ipython=8.3.0 --info | sed '/file name/,/timestamp/d' For quick checking package dependencies (for example, for all python versions)

conda create -n snakes python=3.4 Install different version of Python in new environment

Conda Cheat Sheet by cheat sheet manager

Conda Managing Environments

Lam Hoang — Mon, 10 Oct 2022 16:49:58 +0000

conda info --envs Verify environment you are right now

conda info -e Get a list of all my environmentsActive environment shown with *

conda create --name snowflakes biopython

conda create -n snowflakes biopython Create an environment and install program(s)

conda activate snowflakes Activate the new environment to use it

conda deactivate Deactivate the environment

conda create -n bunnies python=3.9 astroid Create a new environment, specify Python version

conda create -n foo instrain awscli samtools python=3.8 Create a new environment with a set of packages and specific version of Python

conda create -n flowers --clone snowflakes Make exact copy of an environment

conda remove -n flowers --all Delete an environment

conda env list List all envs

conda env export > env.yml Save the current Package-specific environment to a file

conda env export --file env.yml Saving an entire environment to a file

conda env export --from-history > env.yml Save the current Cross-platform compitible environment to a file

conda env create -f env.yml Load the Package-specific environment from a file

conda env update -n coolbase --file environment.yml install and/or update packages from environment.yml

conda env remove --name bamqc Remove Virtual Environment

CONDA_SUBDIR=osx-arm64 conda create -n test_env --dry-run python=3.8 llvm-openmp cython numpy pip "matplotlib-base>=3.0.3" "protobuf >=3.11.2,<4.0.0" "scipy >=1.3.2,<2.0.0" Conda dry run environment on a specific platform

for py in 3.8 3.9 3.10; do echo -e "\n***** python $py *****"; conda create --dry-run --quiet -n __test__ python=$py pandas=1.4.2; done Conda dry run creating an environment and installing packages (pandas 1.4.2) for different python versions

Conda Cheat Sheet by Simple Cheat Sheet

Managing Conda, Miniconda, and Anaconda

Lam Hoang — Mon, 10 Oct 2022 16:40:59 +0000

conda --version Check conda version

conda info Verify conda is installed, check version

conda update conda Update conda package and environment manager

conda update anaconda Update the anaconda meta package

conda update --all Update all packages in the environment

conda update --all -y Update all packages in the environment

Visit conda cheat sheet to get full