Run 3 variables at once in a python for loop.

问题

For loop with multiple variables in python 2.7.

Hello,

I am not certain how to go about this, I have a function that goes to a site and downloads a .csv file. It saves the .csv file in a particular format: name_uniqueID_dataType.csv. here is the code

import requests

name = "name1"
id = "id1" 
dataType = "type1"


def downloadData():
    URL = "http://www.website.com/data/%s" %name #downloads the file from the website. The last part of the URL is the name
    r = requests.get(URL)
    with open("data/%s_%s_%s.csv" %(name, id, dataType), "wb") as code: #create the file in the format name_id_dataType
        code.write(r.content)

downloadData()

The code downloads the file and saves it perfectly fine. I want to run a for loop on the function that takes those three variables each time. The variables will be written as lists.

name = ["name1", "name2"]
id = ["id1", "id2"] 
dataType = ["type1", "type2"]

There will be over 100 different items listed in each list with the same amount of items in each variable. Is there any way to accomplish this using a for loop in python 2.7. I have been doing research on this for the better part of a day but I can't find a way to do it. Please note that I am new to python and this is my first question. Any assistance or guidance would be greatly appreciated.

回答1:

zip the lists and use a for loop:

def downloadData(n,i,d):
    for name, id, data in zip(n,i,d):
        URL = "http://www.website.com/data/{}".format(name) #downloads the file from the website. The last part of the URL is the name
        r = requests.get(URL)
        with open("data/{}_{}_{}.csv".format(name, id, data), "wb") as code: #create the file in the format name_id_dataType
            code.write(r.content)

Then pass the lists to your function when calling:

names = ["name1", "name2"]
ids = ["id1", "id2"]
dtypes = ["type1", "type2"]

downloadData(names, ids, dtypes)

zip will group your elements by index:

In [1]: names = ["name1", "name2"]

In [2]: ids = ["id1", "id2"]

In [3]: dtypes = ["type1", "type2"]

In [4]: zip(names,ids,dtypes)
Out[4]: [('name1', 'id1', 'type1'), ('name2', 'id2', 'type2')]

So the first iteration name,id and data will be ('name1', 'id1', 'type1') and so on..

来源：https://stackoverflow.com/questions/30835740/run-3-variables-at-once-in-a-python-for-loop

标签

python

loops

variables

csv

for-loop