How do I put a single csv row into one list with no duplicates?-CodePudding

I have a csv file with a row that I need to put into a list. An example of the row would be

row A
apple
apple
apple
orange
orange
watermelon

and i need to read that row into a list without the duplicate names, so it would look like

['apple','orange','watermelon']

Here is my current code for this problem:

import csv
start = open('fruits.csv', 'r')
reader = csv.reader(start)
next(reader, None)
for row in reader:
    fruits = [row[1]]
    print(fruits)

My current code just puts each individual line into its own list.

CodePudding user response：

In the code you provided, you are creating a new list with a single item every time you loop though the for loop. Instead, you want to maintain a growing list

import csv
start = open('data.txt', 'r')
reader = csv.reader(start)
next(reader, None)

fruits = [] #define an empty list
for row in reader:
    fruits.append(row[1]) #add to the list

Note that in the data example you provide, there is only one column so it should be row[0] instead of row[1] if we are strictly using that example

To make the list unique, you can convert it into a set which enforces uniqueness:

fruits = set(fruits)

If you want it to be converted back into a list, try the following:

fruits = list(fruits)

Note that this method does not guarantee the order of the list will stay the same.

CodePudding user response：

import csv

data = 'fruits.csv'

fruits_in = []
fruits_out = []

# read csv, append unique items to list
with open(data, 'r') as f:
    reader = csv.reader(f)
    for row in reader:
        if row not in fruits_in: 
            fruits_in.append(row)

# flatten list of lists
for sublist in fruits_in:
    for element in sublist:
        fruits_out.append(element)  

# output: ['row A', 'apple', 'orange', 'watermelon']
print(fruits_out)