Python If Statement and Lists

Question

i'm fairly new to python and am looking for some help. What i would like to do is read a csv file and then use a for loop with an if statement to locate at rows of that data contain a value and print it out with a header and some formatting using f'.

The issue i seem to have it when finding the data using the if statement, im unsure what i can output the data to, which will then enable it to be printed out (the search output could contain multiple rows and columns):

with open(r'data.csv', 'r') as csv_file:
    # loop through the csv file using for loop
    for row in csv_file:
        # search each row of data for the input from the user
        if panel_number in row:
            ??

so do `print(f"
{row}
")` and you will print the content of row as a H1 header — , Sep 08 '22 at 15:48
`??` could be: `print(row)`? You say you want the header, which is generally the first row of the file, so you likely want to save that to a variable so you can print it out when you print the row out. — JNevill, Sep 08 '22 at 15:48
Thanks for that - let me clarify further. So there is multiple rows of data which may match in the 'if statement', and i would like to display these in the console window. is it possible to write these to a list, then print out the list at the end? The data will contain multiple columns and rows. — MattG, Sep 08 '22 at 15:51
shouldnt you read the file content first ?? : https://www.pythontutorial.net/python-basics/python-read-text-file/, https://docs.python.org/3/library/csv.html — pippo1980, Sep 08 '22 at 15:52
@pippo1980 `for row in csv_file:` reads the content line by line. — Barmar, Sep 08 '22 at 15:56
@MattG You can do `matched_lines = []` before the loop, `matched_lines.append(row)` in the `if` statement, and `print(matched_lines)` at the end. — Barmar, Sep 08 '22 at 15:57
shouldnt you read the file content first ?? wirh a csv reader tool/parser https://docs.python.org/3/library/csv.html ?? — pippo1980, Sep 08 '22 at 16:00
ok got it panel_number is the substring to look for in each line — pippo1980, Sep 08 '22 at 16:03
So a follow up question, what about if i just want to search the first column in the CSV? would it be `if panel_number in row[0]:` — MattG, Sep 08 '22 at 16:11
Use the `csv` module to parse the file into fields. See the link in pippo's comment above. — Barmar, Sep 08 '22 at 16:14
Sorry @barmar, i dont follow? should i have before the loop `x.readlines` — MattG, Sep 08 '22 at 16:17

score 0 · Accepted Answer · answered Sep 08 '22 at 16:20

0

Use the csv module. Then in your if statement you can append the row to a list of matches

import csv

matched_rows = []
with open(r'data.csv', 'r') as file:
    file.readline() # skip over header line -- remove this if there's no header
    csv_file = csv.reader(file)
    for row in csv_file:
        # search each row of data for the input from the user
        if row[0] == panel_number:
            matched_rows.append(row)

print(matched_rows)

answered Sep 08 '22 at 16:20

Barmar

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` matched_lines = [] # open the csv file with open(r'data.csv', 'r') as file: # loop through the csv file using for loop file.readline() csv_file = csv.reader(file) for row in csv_file: # search each row of data for the input from the user if row[0] == panel_number: matched_lines.append(row) print(matched_lines)` but i get IndexError: list index out of range – MattG Sep 08 '22 at 16:36
1

You must have blank lines in the file. Add an `if` statement that checks `if len(row) == 0:` and skips that row. – Barmar Sep 08 '22 at 16:40
https://stackoverflow.com/questions/4842057/easiest-way-to-ignore-blank-lines-when-reading-a-file-in-python – pippo1980 Sep 08 '22 at 18:04

Python If Statement and Lists

{row}

1 Answers1