[英]How to read CSV file column by column with Python
I have a CSV file in the following format 我有以下格式的CSV文件
Date, Company, Company, Company
1/1/12, 10, 100, 50
1/2/12, 12, 99, 53
1/3/12, 11, 97, 49
I'm trying to input the data into a PSQL database. 我正在尝试将数据输入到PSQL数据库中。
How would I go about going column by column on the data, so that I would have have something like INSERT INTO table VALUES(company, date, price);
我将如何逐列处理数据,以便拥有类似
INSERT INTO table VALUES(company, date, price);
? ?
Each column corresponds to a company 每列对应一个公司
I'm wondering if something like this would work: 我想知道这样的事情是否会起作用:
import csv
with open("file.csv") as f:
reader = csv.reader(f)
for i, column in enumerate(zip(*reader)):
if i == 0:
_, dates = column
else:
# PY3.x
company, *prices = column
# PY2.7
company, prices = column[0], column[1:]
# Do SQL command here
The idea is to use to transpose the data that is read in by rows with csv.reader
by using zip(*reader). 这个想法是通过使用zip(* reader)来转置使用
csv.reader
通过行读取的数据。 I can't test this out right now but you might have to use zip(*list(reader))
to transpose all the data, however this will load the entire file and probably make a copy. 我目前无法对此进行测试,但是您可能必须使用
zip(*list(reader))
来转置所有数据,但是这将加载整个文件并可能进行复制。 Since your data is small that's probably ok. 由于您的数据很小,因此可以。
For this size of data you can also use pandas. 对于这种大小的数据,您还可以使用熊猫。 Which would just be something like:
就像这样:
import pandas as pd
data = pd.read_csv ("file.csv", index_col=0, parse_dates=False)
dates = data.index.values
for company in data.columns:
price = data[company].values
#SQL command here
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