I have a CSV file with about 2000 records.
Each record has a string, and a category to it:
This is the first line,Line1
This is the second line,Line2
This is the third line,Line3
I need to read this file into a list that looks like this:
data = [('This is the first line', 'Line1'),
('This is the second line', 'Line2'),
('This is the third line', 'Line3')]
How can import this CSV to the list I need using Python?
13 Answers
Using the csv module:
import csv
with open('file.csv', newline='') as f:
reader = csv.reader(f)
data = list(reader)
print(data)
Output:
[['This is the first line', 'Line1'], ['This is the second line', 'Line2'], ['This is the third line', 'Line3']]
If you need tuples:
import csv
with open('file.csv', newline='') as f:
reader = csv.reader(f)
data = [tuple(row) for row in reader]
print(data)
Output:
[('This is the first line', 'Line1'), ('This is the second line', 'Line2'), ('This is the third line', 'Line3')]
Old Python 2 answer, also using the csv module:
import csv
with open('file.csv', 'rb') as f:
reader = csv.reader(f)
your_list = list(reader)
print your_list
# [['This is the first line', 'Line1'],
# ['This is the second line', 'Line2'],
# ['This is the third line', 'Line3']]
Updated for Python 3:
import csv
with open('file.csv', newline='') as f:
reader = csv.reader(f)
your_list = list(reader)
print(your_list)
Output:
[['This is the first line', 'Line1'], ['This is the second line', 'Line2'], ['This is the third line', 'Line3']]
Pandas is pretty good at dealing with data. Here is one example how to use it:
import pandas as pd
# Read the CSV into a pandas data frame (df)
# With a df you can do many things
# most important: visualize data with Seaborn
df = pd.read_csv('filename.csv', delimiter=',')
# Or export it in many ways, e.g. a list of tuples
tuples = [tuple(x) for x in df.values]
# or export it as a list of dicts
dicts = df.to_dict().values()
One big advantage is that pandas deals automatically with header rows.
If you haven't heard of Seaborn, I recommend having a look at it.
See also: How do I read and write CSV files with Python?
Pandas #2
import pandas as pd
# Get data - reading the CSV file
import mpu.pd
df = mpu.pd.example_df()
# Convert
dicts = df.to_dict('records')
The content of df is:
country population population_time EUR
0 Germany 82521653.0 2016-12-01 True
1 France 66991000.0 2017-01-01 True
2 Indonesia 255461700.0 2017-01-01 False
3 Ireland 4761865.0 NaT True
4 Spain 46549045.0 2017-06-01 True
5 Vatican NaN NaT True
The content of dicts is
[{'country': 'Germany', 'population': 82521653.0, 'population_time': Timestamp('2016-12-01 00:00:00'), 'EUR': True},
{'country': 'France', 'population': 66991000.0, 'population_time': Timestamp('2017-01-01 00:00:00'), 'EUR': True},
{'country': 'Indonesia', 'population': 255461700.0, 'population_time': Timestamp('2017-01-01 00:00:00'), 'EUR': False},
{'country': 'Ireland', 'population': 4761865.0, 'population_time': NaT, 'EUR': True},
{'country': 'Spain', 'population': 46549045.0, 'population_time': Timestamp('2017-06-01 00:00:00'), 'EUR': True},
{'country': 'Vatican', 'population': nan, 'population_time': NaT, 'EUR': True}]