ntk38/dsc-0-03-08-understanding-pandas-series-and-dataframes-lab-nyc-ds-career-012819

Understanding Pandas Series and DataFrames - Lab

Introduction

In this lab, let's get some hands on practice working with data cleanup using Pandas.

Objectives

You will be able to:

• Manipulate columns in DataFrames (df.rename, df.drop)
• Manipulate the index in DataFrames (df.reindex, df.drop, df.rename)
• Manipulate column datatypes

import pandas as pd
import matplotlib.pyplot as plt
%matplotlib inline

df = pd.read_csv('turnstile_180901.txt')
print(len(df))
df.head()

197625

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	C/A	UNIT	SCP	STATION	LINENAME	DIVISION	DATE	TIME	DESC	ENTRIES	EXITS
0	A002	R051	02-00-00	59 ST	NQR456W	BMT	08/25/2018	00:00:00	REGULAR	6736067	2283184
1	A002	R051	02-00-00	59 ST	NQR456W	BMT	08/25/2018	04:00:00	REGULAR	6736087	2283188
2	A002	R051	02-00-00	59 ST	NQR456W	BMT	08/25/2018	08:00:00	REGULAR	6736105	2283229
3	A002	R051	02-00-00	59 ST	NQR456W	BMT	08/25/2018	12:00:00	REGULAR	6736180	2283314
4	A002	R051	02-00-00	59 ST	NQR456W	BMT	08/25/2018	16:00:00	REGULAR	6736349	2283384

Practice

Objectives

You will be able to:

• Understand and explain what Pandas Series and DataFrames are and how they differ from dictionaries and lists
• Create Series & DataFrames from dictionaries and lists
• Manipulate columns in DataFrames (df.rename, df.drop)
• Manipulate the index in DataFrames (df.reindex, df.drop, df.rename)
• Manipulate column datatypes

Rename all the columns to lower case

#Your code here

Change the Index to be the Line Names

#Your code here

Painstakingly change the index back

# Your code here

Create another column 'Num_Lines' that is a count of how many lines pass through a station. Then sort your dataframe by this column in descending order.

# Your code here

Write a function to clean a column name.

def clean(col_name):
    cleaned = #Your code here; whatever you want to do to col_name. Hint: think back to str methods.
    return cleaned

#This is a list comprehension. It applies your clean function to every item in the list.
#We then reassign that to df.columns
#You shouldn't have to change anything here.
#Your function above should work appropriately here.
df.columns = [clean(col) for col in df.columns] 

#Checking the output, we can see the results.
df.columns

Compare subway traffic by day of the week. Display this as a graph.

#Your code here

Is there more subway traffic on a weekend or a weekday? Be specific in comparing magnitudes.

#Your code here

Drop a couple of columns

# Your code here