Question

我正在尝试在转置数据帧后在json中显示实际的列名，下面的代码适用于sql的LIMIT 3，但如果我尝试LIMIT 5，请尝试一下会失败吗？

from pandasql import *

pysqldf = lambda q: sqldf(q, globals())

q1 = """
SELECT
 beef as beef, veal as veal, pork as pork, lamb_and_mutton as lamb
FROM
 meat m
LIMIT 5;
"""

meat = load_meat()

df = pysqldf(q1)
#print(df.to_json(orient='records'))

hdf = pd.DataFrame(df)
print(hdf.T.reset_index().set_axis(range(len(hdf.columns)), axis=1, inplace=False).to_json(orient='records'))

错误

    'values have {new} elements'.format(old=old_len, new=new_len))
ValueError: Length mismatch: Expected axis has 6 elements, new values have 4 elements

Answer 1

在override func viewDidAppear(_ animated: Bool) { UIApplication.shared.keyWindow?.rootViewController = self self.view.window?.rootViewController?.dismiss(animated: true, completion: nil) prevVC.reloadViewFromnib() prevVC.dismiss(animated: false, completion: nil) UserDefaults.standard.set(0, forKey: "since_The_Last_Ad") } extension UIViewController { func reloadViewFromnib() { let parent = view.superview view.removeFromSuperview() view = nil parent?.addSubview(view) // This line causes the view to be reloaded } }和T之后，您又添加了一个reset_index，同时columns的长度等于index之前的长度换位，所以您应该使用columns

shape

Answer 2

尝试一下：

df.T.reset_index()\
   .set_axis(range(len(df)+1), axis=1, inplace=False)\
   .to_json(orient='records')

注意：问题是在转置后重命名列，您需要将长度设为原始数据帧中的行数加上索引的1。

输出：

'[{"0":"beef","1":0,"2":4,"3":8,"4":12,"5":16},{"0":"veal","1":1,"2":5,"3":9,"4":13,"5":17},{"0":"pork","1":2,"2":6,"3":10,"4":14,"5":18},{"0":"lamb","1":3,"2":7,"3":11,"4":15,"5":29}]'

用列名而不是索引转置的熊猫数据框会引发ValueError

2 个答案: