在 python 中解压大列表

Question

我必须解压缩这个大列表并将每个项目放入数据库。除了这些数据，一切都很好。

我试过：

([styles], [seasons], [day], [id]) = search_

但是我得到这样的错误：

exception=ValueError('too many values to unpack (expected 4)')>

我使用这样的查询：

insert= "INSERT INTO cantina (styles,seasons,day,id) VALUES (?,?,?,?)"
db.execute(insert,(styles,seasons,day,id))

我知道我犯了一个错误，但是这里每行有 4 个字段，看起来是对的

search_ = [[["Redwine"], ['04'], ['01'], ['81535']],
[["Redwine"], ['04'], ['02'], ['81536']],
[["Redwine"], ['04'], ['03'], ['81537']],
[["Redwine"], ['04'], ['04'], ['81538']],
[["Redwine"], ['04'], ['05'], ['81539']],
[["Redwine"], ['04'], ['06'], ['81540']],
[["Redwine"], ['04'], ['07'], ['81541']],
[["Redwine"], ['04'], ['08'], ['81542']],
[["Redwine"], ['04'], ['09'], ['81543']],
[["Redwine"], ['04'], ['10'], ['81544']],
[["Redwine"], ['04'], ['11'], ['81545']],
[["Redwine"], ['04'], ['12'], ['81546']],
[["Redwine"], ['02'], ['01'], ['97179']],
[["Redwine"], ['02'], ['02'], ['97180']],
[["Redwine"], ['02'], ['03'], ['97181']],
[["Redwine"], ['02'], ['04'], ['97182']],
[["Redwine"], ['02'], ['05'], ['97183']],
[["Redwine"], ['02'], ['06'], ['97184']],
[["Redwine"], ['02'], ['07'], ['97185']],
[["Redwine"], ['02'], ['08'], ['97186']],
[["Redwine"], ['02'], ['09'], ['97187']],
[["Redwine"], ['02'], ['10'], ['97188']],
[["Redwine"], ['02'], ['11'], ['97189']],
[["Redwine"], ['02'], ['12'], ['97190']]]

([styles], [seasons], [day], [id]) = search_

insert= "INSERT INTO cantina (styles,seasons,day,id) VALUES (?,?,?,?)"
db.execute(insert,(styles,seasons,day,id))

编辑：

嗨，Barmar，因为该列表来自我加入的另一个函数四个列表：

def cantina ( cantina_id)
  for ... in ...:
     styles = 
     season  = 
     day = 
     id = 
     result.append([[styles], [season], [day], [id]]])
  return result

和'append'只接受一个参数。

我要处理一些数据，基于'cantina_id'；将其添加到四个列表中并保存到 db

Answer 1

您需要遍历 search_ 并分别处理每一行。

insert= "INSERT INTO cantina (styles,seasons,day,id) VALUES (?,?,?,?)"
for row in search_:
    ([styles], [seasons], [day], [id]) = row
    cur.execute(insert,(styles,seasons,day,id))
db.commit()

如果您更改 cantina 函数使其不创建所有这些单元素列表，您可以使用 executemany()

def cantina ( cantina_id)
  result = []
  for ... in ...:
     styles = 
     season  = 
     day = 
     id = 
     result.append([styles, season, day, id])
  return result

search_ = cantina(some_id)
insert= "INSERT INTO cantina (styles,seasons,day,id) VALUES (?,?,?,?)"
cur.executemany(insert, search_)
db.commit()

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