Lab 03

CSCI 1913 – Introduction to Algorithms, Data Structures, and Program Development

Introduction

In this lab you will be manipulating data that is coming from csv (comma separated values) files

  • You do not have to write code to read files for this lab (that part of the code is provided to you)
  • You do have to understand what the code provided is doing
  • You will manipulate a list of dictionaries

Understanding load(filename)

The docstring for load(filename) says:

“““load the CSV file by name, return list of dictionaries, each dictionary describes one row of the file”“”

You have a few calls to load(filename) in weather_tester.py:

test_file_list = load("test_file.csv")
  • What does test_file_list[0] return?
  • What does test_file_list[0]["Max_Temperature"] return?

Understanding load(filename)

test_file_list = load("test_file.csv")
  • What does test_file_list[0] return? The following dictionary:
{ "Max_Temperature" : 6.0,
  "Min_Temperature" : -9.0, 
  "Precipitation"   : "T",
  "Snow"            : "T",
  "Snow_Depth"      : 9.0 }
  • What does test_file_list[0]["Max_Temperature"] return? 6.0

Retrieving values

What does the following code print?

messy_file_list = load("messy_file.csv")
print(messy_file[0]["Date"])

What does the following code print?

messy_file_list = load("messy_file.csv")
print(messy_file[0]["Date"][0])

Retrieving values

What does the following code print?

messy_file_list = load("messy_file.csv")
print(messy_file[0]["Date"])
"2010-01-01"

What does the following code print?

messy_file_list = load("messy_file.csv")
print(messy_file[0]["Date"][0])
"2"