ErrorsHistogram_6kyu.py

"""
In a factory a printer prints labels for boxes.
The printer uses colors which, for the sake of simplicity,
are named with letters from a to z (except letters u, w, x or z that are for errors).

The colors used by the printer are recorded in a control string.
For example a control string would be aaabbbbhaijjjm meaning that the printer used three times color a,
four times color b, one time color h then one time color a... and so on.

Sometimes there are problems: lack of colors,
technical malfunction and a control string is produced e.g. uuaaaxbbbbyyhwawiwjjjwwxym where errors are reported
with letters u, w, x or z.

You have to write a function hist which given a string will output the errors as a string representing a histogram
of the encountered errors.

Format of the output string:

letter (error letters are sorted in alphabetical order) in a field of 2 characters,
a white space,
number of error for that letter in a field of 6, as many "*" as the number of errors for that letter and "\r".

The string has a length greater or equal to one and contains only letters from a to z.
Bash examples

s="uuaaaxbbbbyyhwawiwjjjwwxym"
hist(s) => "u  2     **\rw  5     *****\rx  2     **"

or with dots to see white spaces:
hist(s) => "u..2.....**\rw..5.....*****\rx..2.....**"

s="uuaaaxbbbbyyhwawiwjjjwwxymzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz"
hist(s) => "u..2.....**\rw..5.....*****\rx..2.....**\rz..31....*******************************"
or printed:
u  2     **
w  5     *****
x  2     **
z  31    *******************************

Notes

    Unfortunately Bash Codewars compresses all white spaces into one.
    You can see another examples in the "Sample tests".
    Translators are welcome for all languages, except for Ruby since the Bash random tests needing Ruby a Ruby reference solution is already there though not yet published.
"""


def hist(s):
    keys = ('u', 'w', 'x', 'z')
    dictionary = {'u': 0, 'w': 0, 'x': 0, 'z': 0}
    result = ""
    
    for char in s:
        if char in keys:
            dictionary[char] += 1
    
    for k in keys:
        hists = ""
        spaces = ""
        
        for i in range(9 - 3 - len(str(dictionary[k]))):
            spaces += " "
        
        for index in range(dictionary[k]):
            hists += "*"
        
        if dictionary[k] != 0:
            result += k + "  " + str(dictionary[k]) + spaces + hists + "\r"
    
    return result[:len(result)-1]