How do I remove empty spaces and lines within a string?

removes multiple spaces (not lines):

print( ' '.join([s for s in S.split(' ') if s.strip()]) )

Here is a way to produce the requested string literal output using only the string literal input, as (was originally) requested:

from re import sub

print(sub('Race\n', 'Race ',
          sub('Missing From\n', 'Missing From ', '\n'.join(
              [sub(' \s', '', line) for line in [line.strip() for line in """
"Missing Since 06/01/1976

Missing From
                                Napa,                               California
Classification Endangered Missing
Sex Female
Race
                                    White
Date of Birth 02/06/1957 (63)
Age 19 years old
Height and Weight 5'2, 130 pounds
Distinguishing Characteristics Caucasian female. Brown hair, hazel eyes."
""".split('\n') if line.strip()]]))))

Output:

"Missing Since 06/01/1976
Missing From Napa, California
Classification Endangered Missing
Sex Female
Race White
Date of Birth 02/06/1957 (63)
Age 19 years old
Height and Weight 5'2, 130 pounds
Distinguishing Characteristics Caucasian female. Brown hair, hazel eyes."

Try this:

import re


def normalize_text(get_text):
    saved_new_lines = []
    counter = 0
    for each_line in get_text.split("\n"):
        if not each_line == "":
            normalize_each_line = re.sub(r'\s+', ' ', each_line.strip())
            if each_line.startswith(" "):
                saved_new_lines[counter-1] += " " + normalize_each_line
            else:
                saved_new_lines.append(normalize_each_line)
                counter += 1
    return "\n".join(saved_new_lines)


print(normalize_text(S))

Output:

Missing Since 06/01/1976
Missing From Napa, California
Classification Endangered Missing
Sex Female
Race White
Date of Birth 02/06/1957 (63)
Age 19 years old
Height and Weight 5'2, 130 pounds
Distinguishing Characteristics Caucasian female. Brown hair, hazel eyes.

@FedericoBaù gave me the hint; so i updated my code (this version dose not have any empty-line checker so it will be much faster than its current status)

Updated:

import re


def normalize_text(get_text):
    saved_new_lines = []
    counter = 0
    for each_line in re.sub(r'\n+', '\n', get_text.strip()).splitlines():
        normalize_each_line = re.sub(r'\s+', ' ', each_line.strip())
        if each_line.startswith(" "):
            saved_new_lines[counter-1] += " {}".format(normalize_each_line)
        else:
            saved_new_lines.append(normalize_each_line)
            counter += 1
    return "\n".join(saved_new_lines)


print(normalize_text(test_string))

I am not into python but as far as i know in php those spaces appear because of \n and \r, To fix you can simply do string.replace("<double-space-here>","") then get the variable and redo the process but this time replace "\n" then "\r". I would be better if you could find a inbuilt method to filter html characters in python.

@Random despite the already very useful answer, I would like to give some more insight regarding the issue you have faced, which is very usual, especially because of how the function strip expectations are.

Logically one may think that it should remove all items within a string, but it does only at the 2 extremity and not 'within' the string, but why?

You should first understand how string a really stored inside Python, they are like 'arrays' (kind of list) really for instance:

string = "  Hello world "

In reality is:

string = [" ", " ", "H", 'e', 'l', 'l', 'o', ' ', 'w', 'o', 'r', 'l', 'd', ' ']

So the strip function go and check whatever character it finds from the left and right of the string and stops until encounters a different character.

Hence it won't loop at the whole string (array) but only from index 0 or index -1!

For more regarding this, I suggest to have a look at array-of-strings-in-c, despite is not Python, Python is written in C and internally has the same implementation.

Some Solutions (Not yet given)

1. Use string.whitespace

        import string
   
        def string_cleaner(str):
            cleaned_string = []
            string_separated = str.split(' ')
            for word in string_separated:
                if word:
                    if word in string.whitespace:
                        del word
                    else:
                        cleaned_string.append(word)
   
            ready_baby = ' '.join(cleaned_string)
            return ready_baby
   
   
        result = string_cleaner(test_string)
   

--> Short form using list comprehension

print(' '.join([s for s in test_string.split(' ') if s and s not in string.whitespace]))

2. Use Function isspace (NO IMPORT NEDDED, pure built-in)

    def string_cleaner(str):
        cleaned_string = []
        string_separated = str.split(' ')
        for word in string_separated:
            if word:
                if word.isspace():
                    del word
                else:
                    cleaned_string.append(word)
   
        ready_baby = ' '.join(cleaned_string)
        return ready_baby
   
   
    result = string_cleaner(test_string)
   
    print(result)
   

--> Short form using list comprehension

print(' '.join([string for string in test_string.split(' ') if string and not string.isspace()]))

Re-visit re.sub function

Here is a reproduction of what re.sub does, note that I added many "useless" variables in order to make the code more explicit:

def string_cleaner(str):

    cleaned_string = []
    string_separated = str.split(' ')
    for word in string_separated:
        if word: # Not Blank line
            remove_whitespace_from_side = word.strip().replace('\n', ' ') # NOTE: we do this because there are multiple \n\n in some string
            separate_each_string = remove_whitespace_from_side.split()
            if separate_each_string:  # NOTE: If empty means that is a useless white spece within a string
                rejoined_sub_string = ' '.join(separate_each_string)
                ready_string = rejoined_sub_string.replace(' ', '\n') # Add again \n
                cleaned_string.append(ready_string)
    ready_to_go = ' '.join(cleaned_string)
    return ready_to_go

result = string_cleaner(test_string)

print(result)

Documentation

• Python Re Sub function

"Return the string obtained by replacing the leftmost non-overlapping occurrences of pattern in string by the replacement repl.".

What it does is similar to C function scanf, more information here.

• list-comprehension
• join method