Cynthia Huang cynthiahqy

How to compress PDF using ghostscript

As a developer, it bothers me when someone sends me a large pdf file compared to the number of pages. Recently, I recieved a 12MB scanned document for just one letter-sized page... so I got to googlin, like I usually do, and found ghostscript!

to learn more abot ghostscript (gs): https://www.ghostscript.com/

What we are interested in, is the gs command line tool, which provides many options for manipulating PDF, but we are interested in compressign those large PDF's into small yet legible documents.

credit goes to this answer on askubuntu forum: https://askubuntu.com/questions/3382/reduce-filesize-of-a-scanned-pdf/3387#3387?newreg=bceddef8bc334e5b88bbfd17a6e7c4f9

Python Version

Do this using instructions from here: https://github.com/pyenv/pyenv

Install brew install pyenv
Configure zsh/bash profile
Install desired python versions
Set global python (for default across machine) and/or local python versions (repo specific)

Virtual Env

Notes to self on infrequent dev environment tasks

Rstats

Don't update R using brew install r because reasons
Using brew install --cask r is okay
Need to reinstall packages after updating R
check package library location in ~/.Renviron

install.packages("pak")

Code for wide to long to wide again

Python MultiIndex artifacts mean that df.pivot() is not the exact inverse of df.melt()

# ---- "load" wide data ----

# df <- tibble::tribble(~country, ~pop, ~capital,
#               "USA",      330,  "Washington D.C.",
#               "AUS",      25,   "Canberra",
#               "JPN",      125,  "Tokyo" )

ISSUE

base::all.equal() poisons numeric columns by recycling the <chr> message, which in turn makes otherwise row-wise operations like dplyr::filter() and dplyr::mutate() behave in an unexpected manner (i.e. returning all FALSE).

This issue arises if just one row has a numeric difference above the tolerance threshold.

For context, I wanted to use all.equal() to filter for rows where both columns have NA values, since the conditions dplyr::near(x,y) and x == y will drop these rows

	# based on:
	# - https://github.com/quarto-dev/quarto-actions/blob/main/examples/quarto-book-gh-pages.yaml
	# - https://github.com/actions/starter-workflows/blob/main/pages/static.yml

	on:
	push:
	branches: main
	pull_request:
	branches: main
	# to be able to trigger a manual build

	#!/usr/bin/python3

	import sys, getopt, os

	try:
	from PyPDF2 import PdfReader, PdfWriter
	# print("pypdf2 Already installed")
	except ImportError as e:
	print("Error -> ", e)

	#!/bin/zsh

	## grab filename without extension

	filepath=$1
	filename=${filepath:r}


	## extract pages as images

	# code to generate csv file of dates to import into notion database

	library(tibble)
	library(dplyr)
	library(lubridate)
	library(stringr)

	df_2024 <- tibble(
	ymd = seq(as.Date("2024-01-01"), as.Date("2024-12-31"), by = "days")
	) \|>

	#!/bin/zsh

	year=$1
	month_names=(Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec)
	month_num=(01 02 03 04 05 06 07 08 09 10 11 12)

	mkdir $year

	for (( idx = 1; idx < 12; idx++ )) ; do
	file_name=$year/${month_num[idx]}-${month_names[idx]}.md