Is there a way for Python to detect whether a value is empty?

Question

I'm trying to write a piece of code that will take certain values in a string and output them. The problem is the dataset I'm working with isn't perfect and there are many parts where the data is empty. I'm looking for a way to get python to ignore the blank values and just continue onwards

rfile = open("1.txt", "r", encoding= "utf8") combos = rfile.readlines() a=0 nfile = open("2.txt ", "w+") numx = 0 for line in combos: x = combos[a] y=(x.split('Points = ')) z= int(y[-1]) numx += 1 print (z) print (numx) rfile.close() nfile.close() exi = input("Press any key to close")

Example of the dataset would be like:

Person 1 | Points = 22 Person 2 | Points = <--- This is the problematic data Person 3 | Points = 15

Any help would be greatly appreciated!

Just to clarify, I want python to check whether z is empty, and if it is to just ignore it. — Fast
– Fast, Commented Jun 21, 2020 at 20:09
Does this answer your question? python: how to check if a line is an empty line — theAlse
– theAlse, Commented Jun 21, 2020 at 20:11

Rayan Ral · Accepted Answer · 2020-06-21 20:11:05Z

1

You can check if variable is empty string, or just None, thy something like: if not value: continue

answered Jun 21, 2020 at 20:11

Rayan Ral

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Comments

alani · Accepted Answer · 2020-06-21 21:15:56Z

After

 y = (x.split('Points = '))

If it is guaranteed that the lines with missing data only have a single space after the =, e.g. 'Person 2 | Points = ' so that y[-1] == '', you can simply do the following to skip over this one and carry on (goes to the start of the next iteration of the for loop):

 if not y: continue

relying on the fact that an empty string counts as a false value.

If it might contain additional whitespace, then you will have to deal with this. There are various options:

test the characters of the string one by one

 for c in y[-1]: # looping over the characters in y[-1] if c != ' ': # if a non-space character is found break # then break from this inner "for" loop else: # but if this loop completed without break continue # then start next iteration of the outer "for" loop

use a regular expression parser (needs import re at the top)

 if re.match('\s*$', y[-1]): continue

just try to convert it to int anyway, and catch the exception if it fails:

 try: z = int(y[-1]) except ValueError: continue

(All of these will still work if the string is indeed empty.)

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