specify number of spaces between pandas DataFrame columns when printing

Question

When you print a pandas DataFrame, which calls DataFrame.to_string, it normally inserts a minimum of 2 spaces between the columns. For example, this code

import pandas as pd

df = pd.DataFrame( {
    "c1" : ("a", "bb", "ccc", "dddd", "eeeeee"),
    "c2" : (11, 22, 33, 44, 55),
    "a3235235235": [1, 2, 3, 4, 5]
} )
print(df)

outputs

       c1  c2  a3235235235
0       a  11            1
1      bb  22            2
2     ccc  33            3
3    dddd  44            4
4  eeeeee  55            5

which has a minimum of 2 spaces between each column.

I am copying DataFarames printed on the console and pasting it into documents, and I have received feedback that it is hard to read: people would like more spaces between the columns.

Is there a standard way to do that?

I see no option in either DataFrame.to_string or pandas.set_option.

I have done a web search, and not found an answer. This question asks how to remove those 2 spaces, while this question asks why sometimes only 1 space is between columns instead of 2 (I also have seen this bug, hope someone answers that question).

My hack solution is to define a function that converts a DataFrame's columns to type str, and then prepends each element with a string of the specified number of spaces.

This code (added to the code above)

def prependSpacesToColumns(df: pd.DataFrame, n: int = 3):
    spaces = ' ' * n
    
    # ensure every column name has the leading spaces:
    if isinstance(df.columns, pd.MultiIndex):
        for i in range(df.columns.nlevels):
            levelNew = [spaces + str(s) for s in df.columns.levels[i]]
            df.columns.set_levels(levelNew, level = i, inplace = True)
    else:
        df.columns = spaces + df.columns
    
    # ensure every element has the leading spaces:
    df = df.astype(str)
    df = spaces + df
    
    return df

dfSp = prependSpacesToColumns(df, 3)
print(dfSp)

outputs

          c1     c2    a3235235235
0          a     11              1
1         bb     22              2
2        ccc     33              3
3       dddd     44              4
4     eeeeee     55              5

which is the desired effect.

But I think that pandas surely must have some builtin simple standard way to do this. Did I miss how?

Also, the solution needs to handle a DataFrame whose columns are a MultiIndex. To continue the code example, consider this modification:

idx = (("Outer", "Inner1"), ("Outer", "Inner2"), ("Outer", "a3235235235"))
df.columns = pd.MultiIndex.from_tuples(idx)

Answer 1

You can accomplish this through formatters; it takes a bit of code to create the dictionary {'col_name': format_string}. Find the max character length in each column or the length of the column header, whichever is greater, add some padding, and then pass a formatting string.

Use partial from functools as the formatters expect a one parameter function, yet we need to specify a different width for each column.

Sample Data

import pandas as pd
df = pd.DataFrame({"c1": ("a", "bb", "ccc", "dddd", 'eeeeee'),
                   "c2": (1, 22, 33, 44, 55),
                   "a3235235235": [1,2,3,4,5]})

---

Code

from functools import partial

# Formatting string 
def get_fmt_str(x, fill):
    return '{message: >{fill}}'.format(message=x, fill=fill)

# Max character length per column
s = df.astype(str).agg(lambda x: x.str.len()).max() 

pad = 6  # How many spaces between 
fmts = {}
for idx, c_len in s.iteritems():
    # Deal with MultIndex tuples or simple string labels. 
    if isinstance(idx, tuple):
        lab_len = max([len(str(x)) for x in idx])
    else:
        lab_len = len(str(idx))

    fill = max(lab_len, c_len) + pad - 1
    fmts[idx] = partial(get_fmt_str, fill=fill)

---

print(df.to_string(formatters=fmts))

            c1      c2      a3235235235
0            a      11                1
1           bb      22                2
2          ccc      33                3
3         dddd      44                4
4       eeeeee      55                5

---

# MultiIndex Output
         Outer                             
        Inner1      Inner2      a3235235235
0            a          11                1
1           bb          22                2
2          ccc          33                3
3         dddd          44                4
4       eeeeee          55                5