Home / Questions / 398684
Accepted
Álvaro Rodríguez Pardo
Asked: 2021-10-17 02:41:57 +0800 CST 2021-10-17 02:41:57 +0800 CST

How to access specific data from a CSV file in Python without using libraries?

  • 772

I have a CSV file about satellites that I need to iterate through a for loop to find out, among other things, how many 'Civilian' satellites the file has. The problem is that when I want to access some specific data I usually get TypeError: object is not subscriptable or TypeError: string indices must be integers.

So far I have done the following:

satelites = open("UCS-Satellite-Database.csv")

for i in satelites:
    print(i)

I have done this to see the rows of the file. So far so good. The problem comes when I want to iterate over the 'Civil' variable or, also, over a specific column, because it always gives me an error. For this I am putting the following:

For the 'Civilian' variable:

for i in satelites:
    print(i['Civil'])

For the second column of the file, which is called 'Users':

for i in satelites:
    print(i['Users'])

Both loops give me error. I have also tried other ways to iterate but with the same error result. If anyone knows what could be wrong and tells me I would appreciate it.

python

1 Answers

  1. Best Answer

    Using the function openyou are opening the file in text mode, so, in your case, when iterating over the variable satelitesyou are iterating over each line of text in the file.

    In this case, the only thing you can do is skip the first line, which is the one that contains the headers, for example using satelites = open("UCS-Satellite-Database.csv")[1:]and then use the function splitwith the separator that is in your CSV file (usually ',' or ';') over each line of text (the variable iin your case) to separate the line into the different elements defined in the header.

    Processing a CSV (or any text file) by hand is tedious, that's why there are libraries that handle common formats such as csv, json or yml.

    • 1