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Python Introduction to pandas Exploring pandas Exploration Methods


In this tutorial, how does this code read data out of users.csv? I'm quite curious, since I haven't even created the file! In other words, my question is this: why does this code work without me even saving a .csv file?

# Setup
import os
import pandas as pd

# We use os.path.join because Windows uses a back slash (\) to separate directories
#  while others use a forward slash (/)
users_file_name = os.path.join('data', 'users.csv')

# Open the file and print out the first 5 lines
with open(users_file_name) as lines:
    for _ in range(5):
        # The `file` object is an iterator, so just get the next line 
Eric M
Eric M
11,545 Points

Hi Mark,

I'm not sure what you mean here when you ask why this works. Where are you running the code and what output are you seeing?

If I run this in a directory that does not have a data subdirectory containing a users.csv it halts with FileNotFoundError: [Errno 2] No such file or directory: 'data\\users.csv'. If I run it with a csv with less than 5 lines (the loop range) it halts with a StopIteration error after printing the available lines.



1 Answer

It just dawned on me... when I cloned the python-introducing-pandas repo, it contains a file subdirectory of data/users.csv, so that's why we're instructed to type this:

users_file_name = os.path.join('data', 'users.csv') users = pd.read_csv(users_file_name, index_col=0)

I'm slightly embarrassed for coming to such an obvious realization! :|

So to be clear, yes, I did save the file when I cloned the repo for this course.