How to print a string at a fixed width?


I have this code (printing the occurrence of the all permutations in a string)

def splitter(str):
    for i in range(1, len(str)):
        start = str[0:i]
        end = str[i:]
        yield (start, end)
        for split in splitter(end):
            result = [start]
            yield result    

el =[];

string = "abcd"
for b in splitter("abcd"):

unique =  sorted(set(el));

for prefix in unique:
    if prefix != "":
        print "value  " , prefix  , "- num of occurrences =   " , string.count(str(prefix));

I want to print all the permutation occurrence there is in string varaible.

since the permutation aren’t in the same length i want to fix the width and print it in a nice not like this one:

value   a - num of occurrences =    1
value   ab - num of occurrences =    1
value   abc - num of occurrences =    1
value   b - num of occurrences =    1
value   bc - num of occurrences =    1
value   bcd - num of occurrences =    1
value   c - num of occurrences =    1
value   cd - num of occurrences =    1
value   d - num of occurrences =    1

How can I use format to do it?

I found these posts but it didn’t go well with alphanumeric strings:

python string formatting fixed width

Setting fixed length with python

Asked By: 0x90



EDIT 2013-12-11 – This answer is very old. It is still valid and correct, but people looking at this should prefer the new format syntax.

You can use string formatting like this:

>>> print '%5s' % 'aa'
>>> print '%5s' % 'aaa'
>>> print '%5s' % 'aaaa'
>>> print '%5s' % 'aaaaa'


  • the % character informs python it will have to substitute something to a token
  • the s character informs python the token will be a string
  • the 5 (or whatever number you wish) informs python to pad the string with spaces up to 5 characters.

In your specific case a possible implementation could look like:

>>> dict_ = {'a': 1, 'ab': 1, 'abc': 1}
>>> for item in dict_.items():
...     print 'value %3s - num of occurances = %d' % item # %d is the token of integers
value   a - num of occurances = 1
value  ab - num of occurances = 1
value abc - num of occurances = 1

SIDE NOTE: Just wondered if you are aware of the existence of the itertools module. For example you could obtain a list of all your combinations in one line with:

>>> [''.join(perm) for i in range(1, len(s)) for perm in it.permutations(s, i)]
['a', 'b', 'c', 'd', 'ab', 'ac', 'ad', 'ba', 'bc', 'bd', 'ca', 'cb', 'cd', 'da', 'db', 'dc', 'abc', 'abd', 'acb', 'acd', 'adb', 'adc', 'bac', 'bad', 'bca', 'bcd', 'bda', 'bdc', 'cab', 'cad', 'cba', 'cbd', 'cda', 'cdb', 'dab', 'dac', 'dba', 'dbc', 'dca', 'dcb']

and you could get the number of occurrences by using combinations in conjunction with count().

Answered By: mac

I find using str.format much more elegant:

>>> '{0: <5}'.format('s')
's    '
>>> '{0: <5}'.format('ss')
'ss   '
>>> '{0: <5}'.format('sss')
'sss  '
>>> '{0: <5}'.format('ssss')
'ssss '
>>> '{0: <5}'.format('sssss')

In case you want to align the string to the right use > instead of <:

>>> '{0: >5}'.format('ss')
'   ss'

Edit 1:
As mentioned in the comments: the 0 in '{0: <5}' indicates the argument’s index passed to str.format().

Edit 2:
In python3 one could use also f-strings:

for i in range(1,6):
    s = sub_str*i
'    s'
'   ss'
'  sss'
' ssss'


for i in range(1,5):
    s = sub_str*i
's    '
'ss   '
'sss  '
'ssss '

of note, in some places above, ' ' (single quotation marks) were added to emphasize the width of the printed strings.

Answered By: 0x90

Originally posted as an edit to @0x90’s answer, but it got rejected for deviating from the post’s original intent and recommended to post as a comment or answer, so I’m including the short write-up here.

In addition to the answer from @0x90, the syntax can be made more flexible, by using a variable for the width (as per @user2763554’s comment):

'{0: <{width}}'.format('sss', width=width)

Further, you can make this expression briefer, by only using numbers and relying on the order of the arguments passed to format:

'{0: <{1}}'.format('sss', width)

Or even leave out all numbers for maximal, potentially non-pythonically implicit, compactness:

'{: <{}}'.format('sss', width)

Update 2017-05-26

With the introduction of formatted string literals (“f-strings” for short) in Python 3.6, it is now possible to access previously defined variables with a briefer syntax:

>>> name = "Fred"
>>> f"He said his name is {name}."
'He said his name is Fred.'

This also applies to string formatting

>>> width=10
>>> string = 'sss'
>>> f'{string: <{width}}'
'sss       '
Answered By: joelostblom

format is definitely the most elegant way, but afaik you can’t use that with python’s logging module, so here’s how you can do it using the % formatting:

formatter = logging.Formatter(
    fmt='%(asctime)s | %(name)-20s | %(levelname)-10s | %(message)s',

Here, the - indicates left-alignment, and the number before s indicates the fixed width.

Some sample output:

2017-03-14 14:43:42,581 | this-app             | INFO       | running main
2017-03-14 14:43:42,581 | this-app.aux         | DEBUG      | 5 is an int!
2017-03-14 14:43:42,581 | this-app.aux         | INFO       | hello
2017-03-14 14:43:42,581 | this-app             | ERROR      | failed running main

More info at the docs here:

Answered By: ryantuck
>>> print(f"{'123':<4}56789")
123 56789
Answered By: Miladiouss

This will help to keep a fixed length when you want to print several elements at one print statement.

25s formats a string with 25 spaces, left justified by default.

5d formats an integer reserving 5 spaces, right justified by default.

print('{:25s} {:32s} {:35s} '.format("Name","Country","Age"))
print('{:25s} {:30s} {:5d} '.format(members[0],"Srilanka",20))
print('{:25s} {:30s} {:5d} '.format(members[1],"Australia",25))
print('{:25s} {:30s} {:5d} '.format(members[2],"England",30))

And this will print

Name                      Country                          Age
Niroshan                  Srilanka                          20
Brayan                    Australia                         25
Kate                      England                           30
Answered By: Niroshan Ratnayake

I found ljust() and rjust() very useful to print a string at a fixed width or fill out a Python string with spaces.

An example


# expected output  

For your case, you case use fstring to print

for prefix in unique:
    if prefix != "":
        print(f"value  {prefix.ljust(3)} - num of occurrences = {string.count(str(prefix))}")

Expected Output

value  a   - num of occurrences = 1
value  ab  - num of occurrences = 1
value  abc - num of occurrences = 1
value  b   - num of occurrences = 1
value  bc  - num of occurrences = 1
value  bcd - num of occurrences = 1
value  c   - num of occurrences = 1
value  cd  - num of occurrences = 1
value  d   - num of occurrences = 1

You can change 3 to the highest length of your permutation string.

Answered By: Abu Shoeb