CODEWITHSUNDEEP
python
Lss
Lss

Reputation: 75

Looping through a string and only returning certain characters. Python

I have a problem when creating a function that's supposed to first return lowercase letters, "_" and "." and then uppercase letters, " " and "|" in that order. My version seems to return numbers and special characters like <>@ too which I don't want it to do, It's only supposed to read through the input string once and I don't know if that's achieved with my code.

My code is:

def split_iterative(n):
    splitted_first = ""
    splitted_second = ""
    for i in n:
        if i == i.lower() or i == "_" or i == ".":
            splitted_first = splitted_first + i
        elif i == i.upper() or i == " " or i == "|":
            splitted_second = splitted_second + i
    return splitted_first + splitted_second

if I do split_iterative("'lMiED)teD5E,_hLAe;Nm,0@Dli&Eg ,#4aI?rN@T§&e7#4E #<(S0A?<)NT8<0'")) it returns "'li)te5,_he;m,0@li&g ,#4a?r@§&e7#4 #<(0?<)8<0'MEDDELANDEINTESANT" which is incorrect as it should eliminate all those special characters and numbers. How do I fix this? It should return ('lite_hemligare', 'MEDDELANDE INTE SANT')

Upvotes: 1

Views: 1125

Answers (5)

Oluwafemi Sule
Oluwafemi Sule

Reputation: 38952

You can make use of two lists while walking through characters of your text.

You can append lowercase, underscore, and stop characters to one list then uppercase, space and pipe characters to the other.

Finally return a tuple of each list joined as strings.

def splittext(txt):
  slug, uppercase_letters = [], []
  slug_symbols = {'_', '.'}
  uppercase_symbols = {' ', '|'}

  for letter in txt:
    if letter.islower() or letter in slug_symbols:
      slug.append(letter)
    if letter.isupper() or letter in uppercase_symbols:
      uppercase_letters.append(letter)

  return ''.join(slug), ''.join(uppercase_letters)


txt="'lMiED)teD5E,_hLAe;Nm,0@Dli&Eg ,#4aI?rN@T§&e7#4E #<(S0A?<)NT8<0'"
assert splittext(txt) == ("lite_hemligare", "MEDDELANDE INTE SANT")

Upvotes: 0

SuperKogito
SuperKogito

Reputation: 2966

You can use ASCII values for the filtering of characters:

def split_iterative(n):
    splitted_first = ""
    splitted_second = ""
    for i in n:
        if ord(i) in range(97,122) or i == "_" or i == ".":
            splitted_first = splitted_first + i
        elif ord(i) in range(65,90) or i == " " or i == "|":
            splitted_second = splitted_second + i
    return (splitted_first , splitted_second)

Upvotes: 0

Danny Mcwaves
Danny Mcwaves

Reputation: 179

This is because you are iterating through a string. The lowercase of the special characters is the same as the character. i.e.. '#'.lower() == '#'. hence it'll return '#' and all other special characters. you should explicitly check for alphabets using the isalpha() method on strings. (i.isalpha() and i.lower() == i) or i == '_' or i == '.'

Upvotes: 1

jDo
jDo

Reputation: 4010

You could try this:

def f(input_string):
    str1 = str2 = ""
    for character in input_string:
        if character.isalpha():
            if character.islower():
                str1 += character
            else:
                str2 += character
        elif character in "_.":
            str1 += character
        elif character in " |":
            str2 += character
    return str1, str2

Output:

>>> input_string = "'lMiED)teD5E,_hLAe;Nm,0@Dli&Eg ,#4aI?rN@T§&e7#4E #<(S0A?<)NT8<0'"
>>> 
>>> print f(input_string)
('lite_hemligare', 'MEDDELANDE INTE SANT')
>>>

Upvotes: 1

amiin
amiin

Reputation: 28

First, to make it return a list don't return the concatenated string but a list

Second, you are not checking or filtering out the characters, one way would be by checking if the character is a letter using isalpha() method

something like this:

def split_iterative(n):
splitted_first = ""
splitted_second = ""
for i in n:
    if (i.isalpha() and i == i.lower()) or i == "_" or i == ".":
        splitted_first = splitted_first + i
    elif (i.isalpha() and i == i.upper()) or i == " " or i == "|":
        splitted_second = splitted_second + i
#returns a list you can make it a variable if you need
return [splitted_first, splitted_second]

Upvotes: 0

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