Remove a line that contains a word from a list

Question

Having a string like this one:

machine1 volumename1 space1
machine1 volumename2 space2
machine2 volumename1 space1
machine2 volumename2 space2
machine3 volumename1 space1

I would like to remove all the lines containing one element of a list, for example:

list = ["machine1", "machine3"]

Receiving at the end something like this:

machine2 volumename1 space1
machine2 volumename2 space2

I tried with this, but it returns a list, and I would like to not change the original format of the string and I would like to use a list of machines as an input:

output = str([line for line in output.split('\n') if 'machine1' not in line and 'machine3' not in line])

score 3 · Accepted Answer · answered Jul 21 '21 at 09:19

3

Try using \n, and any for list:

lst = ["machine1", "machine3"]
print('\n'.join([line for line in output.splitlines() if not any(i in line for i in lst)]))

Output:

machine2 volumename1 space1
machine2 volumename2 space2

answered Jul 21 '21 at 09:19

U13-Forward

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The explicit list is unnecessary and slightly wasteful; `join()` can handle a generator expression. – tripleee Jul 21 '21 at 09:21
2

@tripleee Well for performance I usually use the brackets, check [this](https://stackoverflow.com/questions/9060653/list-comprehension-without-in-python/9061024#9061024) out. – U13-Forward Jul 21 '21 at 09:22
@tripleee haha yeah from raymond hettinger. – U13-Forward Jul 21 '21 at 09:26

tripleee · Answer 2 · 2021-07-21T09:24:22.663

Just '\n'.join() the list back together after filtering it.

output = '\n'.join(line for line in output.splitlines() if 'machine1' not in line and 'machine3' not in line)

If you are explicitly examining only the first field and the whole first field, the code will be both more precise and robust and possibly even faster if you explicitly split() out the first field and examine only that.

output = '\n'.join(line for line in ouput.splitlines()
    if line.split()[0] not in ['machine1', 'machine3'])

score 1 · Answer 3 · answered Jul 21 '21 at 09:22

Use the any keyword to avoid any items from your list, and instead of converting to a string with str use "connector".join(list) as shown in the print function.

As a side-note, you really shouldn't use keywords like list to name your variables, so I've changed that variable name to lst.

output = """machine1 volumename1 space1
machine1 volumename2 space2
machine2 volumename1 space1
machine2 volumename2 space2
machine3 volumename1 space1"""
lst = ["machine1", "machine3"]

output = [line for line in output.split('\n') if not any(w in line for w in lst)]
print("\n".join(output))

Output:

machine2 volumename1 space1
machine2 volumename2 space2

Remove a line that contains a word from a list

3 Answers3