Output_string

Hello again so I have this code that takes all the punctuation out of the input (this is from a python textbook) but my question is how does the program know what output_string is equal too

punctuation = "#()*+,-/:<=>?\@^_`{|}~[]"

print (" ")

print ("*****")

print (" ")

input_string = input (" Enter text string: ")

output_string = " "

space_flagged = False


for char in input_string:
if char == '.':
print (output_string)
output_string = ' '

elif char not in punctuation:
output_string += char
space_flagged = False

else:
if not space_flagged:
output_string += ' '
space_flagged = True

print (output_string)

I have tried just running bits of the code and when I do the program prints output_string as nothing. Also what is a flag?

Book: Discard it.

flags: Just a variable name. Common meaning is the data is Boolean. True or False. Suppose you run a complicated algorithm and but merely want to know if a pattern was found. You'd "set a flag" or make sure to clear it. Or, to tell the regular expression search that you want to ignore case, you'd "set a flag".

ah that makes sense but how does the program know what output_string is because the value if just empty quotes

look through the program you posted line by line. Some places you'll see
output_string += char
or
output_string= ' '

These statements change output_string
There's still another few places of
print(output_string)

I can't figure out why the book author would want to remove punctuation from a sentence, or why their algorithm happens to be the smartest way to do it.

On periods the program displays its current collection and a new line.

Sometimes it sticks in spaces.

Whatever. I still say "discard your book".

Really? I can think of several reasons That’s the way you begin when you want to read a text into a corpus of some kind.

I think the original script was meant the parse the text into words sentence by sentence, and that’s why periods are handled specially. Ugly coding though.