zachmayer

#Code to re-create John Hussman's Recession warning index
#http://www.hussmanfunds.com/wmc/wmc110801.htm
#R code by Zach Mayer

rm(list = ls(all = TRUE)) #CLEAR WORKSPACE
library(quantmod)

#################################################
# 1. Credit spreads
#################################################

syntacticsugar

INSERT INTO pet (id, name, breed, age, dead)
	VALUES (5, "shimmer", "unicorn", 500, 1);

INSERT INTO pet (id, name, breed, age, dead)
	VALUES (6, "water bottle", "faun", 4, 1);

INSERT INTO pet (id, name, breed, age, dead)
	VALUES (7, "luis", "elephant", 282, 1);

INSERT INTO pet (id, name, breed, age, dead)

bdewilde

# helpful functions for classification/regression training
# http://cran.r-project.org/web/packages/caret/index.html
library(caret)

# get indices of data.frame columns (pixels) with low variance
badCols <- nearZeroVar(train)
print(paste("Fraction of nearZeroVar columns:", round(length(badCols)/length(train),4)))

# remove those "bad" columns from the training and cross-validation sets
train <- train[, -badCols]

mrdwab

LinearizeNestedList <- function(NList, LinearizeDataFrames=FALSE,
                                NameSep="/", ForceNames=FALSE) {
    # LinearizeNestedList:
    #
    # https://sites.google.com/site/akhilsbehl/geekspace/
    #         articles/r/linearize_nested_lists_in_r
    #
    # Akhil S Bhel
    # 
    # Implements a recursive algorithm to linearize nested lists upto any

adrienne

Various handy bits and bobs relating to SQL (and the mySQL RDBMS in particular).

# Dump all databases from CLI:

$ mysqldump -h [server] -u root --password=password --default-character-set=utf8 --set-charset --all-databases > all_dbs.sql

# Restore all databases from CLI:

$ mysql -u root --password=password --default-character-set=utf8 --set-charset < all_dbs.sql

martincr

PostgreSQL Cheat Sheet
======================

CREATE DATABASE
CREATE DATABASE dbName;

CREATE TABLE (with auto numbering integer id)
CREATE TABLE tableName (
 id serial PRIMARY KEY,
 name varchar(50) UNIQUE NOT NULL,

hofmannsven

MySQL

Getting started

• http://www.sqlteaching.com/
• https://www.codecademy.com/learn/learn-sql
• https://www.codecademy.com/catalog/language/sql

Related tutorials

• MySQL-CLI
• Analyzing Business Metrics

bsweger

Useful Pandas Snippets

A personal diary of DataFrame munging over the years.

Data Types and Conversion

Convert Series datatype to numeric (will error if column has non-numeric values)
(h/t @makmanalp)

jtleek

## Load libraries
library(XML)
library(dplyr)
library(RCurl)

## Get the results for a specific term
scrape_term = function(search_term,npages){
  base_url = "http://scholar.google.com/scholar?"
  search_string = paste0("q=",paste0(strsplit(search_term," ")[[1]],collapse="+"))
  dat = data.frame(NA,nrow=10*npages,ncol=3)

markglenfletcher

SQL

Statements always end with a semi-colon ;

Statement breakdown:

CREATE TABLE table_name (
  column_1 data_type,
  column_1 data_type
);