Need help in finding the row of CSV which contains the values in array

Question

I have an array LiveTick = ['ted3m index','US0003m index','USGG3m index'] and I am reading a CSV file book1.csv . I have to find the row which contains the values in csv.

For example, 15th row will contain ted3m index 500 | 600 ted3m index 500 | 600 and 20th row will contain US0003m index 800 | 900 US0003m index 800 | 900 and likewise.

I then have to get the values contained in the row and parse it for each value contained in array LiveTick . How do I proceed? Below is my sample code:

 with open('C:\\blp\\book1.csv', 'r') as f:
   reader = csv.reader(f, delimiter=',')
   writer = csv.writer(outf)
   for row in reader:
      for list in LiveTick:
         if list in row:
            print ('Found: {}'.format(row))

Answer 1

You can use pandas, it's pretty fast and will do all reading, writing and filtering job for you out of the box:

import pandas as pd

df = pd.read_csv('C:\\blp\\book1.csv')
filtered_df = df[df['your_column_name'].isin(LiveTick)]

# now you can save it
filtered_df.to_csv('C:\\blp\\book_filtered.csv')

Answer 2

You have the right idea, but there are a few improvements you can make:

• Instead of a nested for loop which doesn't short-circuit, use any to compare the first column to multiple values.
• Write to your csv as you go along instead of just print . This is memory-efficient, as you hold in memory only one line at any one time.
• Define outf as an open object in your with statement.
• Do not shadow built-in list . Use another identifier, eg i , for elements in LiveTick .

Here's a demo:

with open('in.csv', 'r') as f, open('out.csv', 'wb', newline='') as outf:
    reader = csv.reader(f, delimiter=',')
    writer = csv.writer(outf, delimiter=',')
    for row in reader:
        if any(i in row[0] for i in LiveTick):
            writer.writerow(row)