[pandas] array to dataframe, dataframe to JSON, dataframe modify column order

Record some problems encountered in the project .

import numpy as np
a = np.array((0.2,0.5,0.9,1.5))

Yes a To transpose ：

import numpy as np
a = np.array((0.2,0.5,0.9,1.5))
a_new = a.reshape(1,4)

1、array turn DataFrame

import numpy as np
import pandas as pd
a = np.array((0.2,0.5,0.9,1.5))
a_new = a.reshape(1,4)
df_a = pd.DataFrame(a_new)

Change column names ：

import numpy as np
import pandas as pd
a = np.array((0.2,0.5,0.9,1.5))
a_new = a.reshape(1,4)
df_a = pd.DataFrame(a_new)
df_a.columns = ['a', 'b', 'c', 'd'] # Name 

2、DataFrame turn json

import numpy as np
import pandas as pd
a = np.array((0.2,0.5,0.9,1.5))
a_new = a.reshape(1,4)
df_a = pd.DataFrame(a_new)
df_a.columns = ['a', 'b', 'c', 'd'] # Name 
# DataFrame turn jason
df_a_new = df_a.to_json(orient="columns")

3、DataFrame Change the order of columns

stay df_a The order of columns in is a、b、c、d

The order we need now is d、b、c、a

import numpy as np
import pandas as pd
a = np.array((0.2,0.5,0.9,1.5))
a_new = a.reshape(1,4)
df_a = pd.DataFrame(a_new)
df_a.columns = ['a', 'b', 'c', 'd'] # Name 
df_a_p = df_a[["d","b","c","a"]]

attach , Give away one
Splicing DataFrame,A,B,C, D four DataFrame
ABCD = pd.concat([A,B,C, D], axis=1)

Reference resources ：
https://blog.csdn.net/qq_27328197/article/details/113823989