How can I filter out a List from a .txt file using list comprehension?

Question

I am taking a Python class and I can’t figure out a take home quiz. I am using IDLE to write the code.

We have to load a file called names.txt into a list. The file contains the following:

Joe Smith
000000
Jeff Mitchell
xxxxxxx
Benjamin Grant
12346

I need to filter out lines that contain the "xxxxxxx" or numbers. I am attempting to use list comprehension with the following code:

> names = open(r'C:UsersabcdseDocumentsPythonnames1.txt','r')
> names_contents = names.read()
> filtered_names = [n for n in names_contents if n !='xxxxxxx']
> names.close()
> print(filtered_names)

However, when I print the filtered_names output, names are not being filtered and rather than appearing in a dropdown format, they appear like this:

[‘J’, ‘o’, ‘e’, ‘ ‘, ‘S’, ‘m’, ‘i’, ‘t’, ‘h’, ‘n’, ‘0’, ‘0’, ‘0’, ‘0’, ‘0’, ‘0’, ‘n’, ‘J’, ‘e’, ‘f’, ‘f’, ‘ ‘, ‘M’, ‘i’, ‘t’, ‘c’, ‘h’, ‘e’, ‘l’, ‘l’, ‘n’, ‘x’, ‘x’, ‘x’, ‘x’, ‘x’, ‘x’, ‘x’, ‘n’, ‘B’, ‘e’, ‘n’, ‘j’, ‘a’, ‘m’, ‘i’, ‘n’, ‘ ‘, ‘G’, ‘r’, ‘a’, ‘n’, ‘t’, ‘n’, ‘1’, ‘2’, ‘3’, ‘4’, ‘6’, ‘n’]

What am I doing wrong here? Is it possible to filter out both, the "xxxxxxx" and numbers?

Thank you for your support as I get started with code.

Asked By: EEO

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Source

Answer 1

You can use readlines to read the data and list comprehension to filter out xxx

ss = '''
Joe Smith
000000
Jeff Mitchell
xxxxxxx
Benjamin Grant
12346
'''.strip()

with open('names.txt','w') as f: f.write(ss)  # write data file

###############################


with open('names.txt') as f:
   lns = f.readlines()
   xx = [ln.strip() for ln in lns if ln.strip() != 'xxxxxxx']
   
print('n'.join(xx))

Output

Joe Smith
000000
Jeff Mitchell
Benjamin Grant
12346

Answered By: Mike67

Answer 2

names_contents is a string, so you are comparing a string against char in this line of code n !='xxxxxxx'. So first you have to split the string into list of strings representing each line. Try this

lines = names_contents.split("n")
filtered_names = [n for n in lines if n !='xxxxxxx']

Answered By: SriDatta Yalla

Answer 3

You were almost there

names = open(r'C:UserseesquDocumentsPythonnames1.txt','r')
name_contents = names.readlines()  # list of lines
filtered_names = [n for n in name_contents if (not n.isnumeric() or n != 'xxxxxxx']

Might want to look things up using your favorite search engine before posting here though. This is a very trivial question.

Answered By: loonatick

Answer 4

The values you want to remove
filter_vals = 'xxxxxxxn'

Read the file

with open('64797525.txt') as f:
    out = [i.strip() for i in f.readlines() if i not in filter_vals] # remove what's in the list

print(out)
['Joe Smith', '000000', 'Jeff Mitchell', 'Benjamin Grant', '12346']

Answered By: Kenan

How can I filter out a List from a .txt file using list comprehension?

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