python - 在 for-in 循环之间添加暂停

Question

我有一个访问网站超过 100 次的脚本，并且希望在每个项目之间添加一个小的延迟。另外，如果可能的话，可以添加倒计时或进程栏，显示状态或剩余项目数。代码示例如下；

import pandas as pd

urls = ['https://vpic.nhtsa.dot.gov/api/vehicles/GetModelsForMakeIdYear/makeId/440/vehicletype/car?format=csv', 
    'https://vpic.nhtsa.dot.gov/api/vehicles/GetModelsForMakeIdYear/makeId/441/vehicletype/car?format=csv', 
    'https://vpic.nhtsa.dot.gov/api/vehicles/GetModelsForMakeIdYear/makeId/442/vehicletype/car?format=csv', 
    'https://vpic.nhtsa.dot.gov/api/vehicles/GetModelsForMakeIdYear/makeId/443/vehicletype/car?format=csv', 
    'https://vpic.nhtsa.dot.gov/api/vehicles/GetModelsForMakeIdYear/makeId/445/vehicletype/car?format=csv', 
    'https://vpic.nhtsa.dot.gov/api/vehicles/GetModelsForMakeIdYear/makeId/448/vehicletype/car?format=csv']             


dfs = [pd.read_csv(url) for url in urls]
df = pd.concat(dfs, ignore_index=True)                                                                                      
df.to_csv('foo.csv')                                                                                                        

Answer 1

import time 
dfs = []
num = len(urls)
for i, url in enumerate(urls):
  dfs.append(pd.read_csv(url))
  print 'Process {}, {} left'.format(i+1, num-i-1)
  time.sleep(2)