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]
result.extend(split)
yield result
el =[];
string = "abcd"
for b in splitter("abcd"):
el.extend(b);
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:
This question is related to
python
python-3.x
python-2.7
format
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
print('123.00'.rjust(9))
print('123456.89'.rjust(9))
# expected output
123.00
123456.89
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.
>>> print(f"{'123':<4}56789")
123 56789
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')
'sssss'
If 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:
sub_str='s'
for i in range(1,6):
s = sub_str*i
print(f'{s:>5}')
' s'
' ss'
' sss'
' ssss'
'sssss'
or:
for i in range(1,5):
s = sub_str*i
print(f'{s:<5}')
's '
'ss '
'sss '
'ssss '
'sssss'
of note, in some places above, ' '
(single quotation marks) were added to emphasize the width of the printed strings.
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):
width=10
'{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
:
width=10
'{0: <{1}}'.format('sss', width)
Or even leave out all numbers for maximal, potentially non-pythonically implicit, compactness:
width=10
'{: <{}}'.format('sss', width)
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 '
This will Help to Keep a fixed length when you want to print several elements at one print statement
25s format a string with 25 spaces, left justified by default
5d format an integer reserving 5 spaces, right justified by default
members=["Niroshan","Brayan","Kate"]
print("__________________________________________________________________")
print('{:25s} {:32s} {:35s} '.format("Name","Country","Age"))
print("__________________________________________________________________")
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))
print("__________________________________________________________________")
25s format a string with 25 spaces, left justified by default
5d format an integer reserving 5 spaces, right justified by default
And this will print
__________________________________________________________________
Name Country Age
__________________________________________________________________
Niroshan Srilanka 20
Brayan Australia 25
Kate England 30
__________________________________________________________________
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: https://docs.python.org/2/library/stdtypes.html#string-formatting-operations
Source: Stackoverflow.com