Installation

pyenv activate guild # guild is the environment name
pip3 install numpy pandas # install numpy and pandas in the 'guild' environment
jupyter notebook # start up jupyter

cheatsheet

transactions_df is a Pandas Dataframe that looks like this:

  order_id product quantity price customer_id transaction_date
0 1 Pasta 43 $11.39 4 17/6/19
1 2 Lamb 71 $3.72 5 4/9/19
2 3 Cake 81 $3.09 76 24/10/19
3 4 Wine 69 $7.09 20 29/4/19 
# overview
import pandas as pd
tranx = pd.read_csv('transactions.csv')
tranx.info()
tranx.shape
tranx.head(10) # first 10 rows
tranx["price"].describe()
transactions['price'].dtype

# null
tranx.isnull()
tranx.notnull()
tranx.dropna()
tranx.dropna(subset=["price"])
tranx.fillna()
tranx.fillna(value={"price":0.0, "quantity":0})

# selecting
tranx["price"] # column 'price'
tranx.iloc[0] # first row
tranx.nlargest(2,columns=["price"])
tranx.nsmallest(2,columns=["price"])

# sorting & grouping
tranx.sort_values(["price"], ascending=False)
tranx.groupby("customer_id").sum("price")
tranx.groupby("customer_id").sum("price")

# filter row
new_df = tranx[(tranx['product']=='Honey')['price']==0.0)]

# column operations
### strip_off_dollar is a function that takes 1 parameter
tranx['price'] = tranx['price'].apply(strip_off_dollar)
tranx['total'] = tranx['price'] * tranx["quantity"]