Python：在Pandas中的列标题后插入连字符

Question

I have created a dataframe in Python Pandas as below:

import pandas as pd
import os   
cols = ('Name','AGE','SAL')
df = pd.read_csv("C:\\Users\\agupt80\\Desktop\\POC\\Python\\test.csv",names = cols)
print(df)

When I am printing dataframe I am getting below output:

    Name  AGE  SAL
0   Amit   32  100
1  gupta   33  200
2  hello   34  300
3   Amit   33  100

Please help is letting me know, how can I insert a Hyphen "-" line after column header like below:

    Name  AGE  SAL
------------------------
0   Amit   32  100
1  gupta   33  200
2  hello   34  300
3   Amit   33  100

Answer 1

I don't know of any pandas customization option for printing separators, but you can just print the df to a string, and then insert the line yourself. Something like this:

string_repr = df.to_string().splitlines()
string_repr.insert(1, "-" * len(string_repr[0]))
out = '\n'.join(string_repr)


>>> print(out)
    Name  AGE  SAL
------------------
0   Amit   32  100
1  gupta   33  200
2  hello   34  300
3   Amit   33  100

Answer 2

You could do something like this:

import pandas as pd

df = pd.DataFrame([
    ['Amit', 32, 100],
    ['gupta', 33, 200],
    ['hello', 34, 100],
    ['Amit', 33, 100]],
    columns=['Name', 'AGE', 'SAL'])
lines = df.to_string().splitlines()
num_hyphens = max(len(line) for line in lines)
lines.insert(1, '-' * num_hyphens)
result = '\n'.join(lines)
print(result)

Output:

    Name  AGE  SAL
------------------
0   Amit   32  100
1  gupta   33  200
2  hello   34  100
3   Amit   33  100

You can change the calculation of num_hyphens depending on how exactly you want your output to look like. For example you could do:

num_hyphens = 2 * len(lines[0]) - len(lines[0].strip())

To get:

    Name  AGE  SAL
----------------------
0   Amit   32  100
1  gupta   33  200
2  hello   34  100
3   Amit   33  100

Note: If the DataFrame has a named index, to_string will output an additional header line with the name of the index. In that case you could choose to remove that line (replace it with the hyphens) add the hyphens after it (at position 2 instead of 1).

Answer 3

you need,

#shift the values one level 
df=df.shift(1)
#fill the first row with hyphen
df.iloc[0]='----'

output

Name  AGE   SAL
----  ----  ----
Amit3 2     100
gupta 33    200
hello 34    300