循环读取日志文件并打印所需结果（python）

Question

I am trying to read 3 log files and use parsing to extract the requered information; I need this code to run in a loop and obtain new lines if they meet requered parameters.

I wrote the following code:

import os

x_list = []
y_list = []
z_list = []

x_log = open('x.txt')
for line in x_log:
    line = line.rstrip()
    if 'error' in line:
        x = line
        for x in x_log:
            if not x in x_log:
                x_list.append(x)
                print('ERROR1',x)

y_log = open('y.txt')
for line in y_log:
    line = line.rstrip()
    if 'error' in line:
        x = line
        for x in y_list:
            if not x in y_list:
                y_list.append(x)
                print('ERROR2',x)

z_log = open('z.txt')
for line in z_log:
    line = line.rstrip()
    if 'error' in line:
        x = line
        for x in z_log:
            if not x in z_list:
                z_list.append(x)
                print('ERROR3',x)

what I am trying to accomplish: 1. read the file. 2. search for relevant line. 3. if the information does not exist in the list, append to list. 4. print line.

I need help setting a while loop, and I am decently doing something wrong while comparing the line to the content of the list.

UPDATE1:

Ok so I managed to get my code to work by adding:

and line not in x_list:

to my original line:

if 'error' in line:

so now I got:

if 'error' in line and line not in x_list:

full code:

x_list = []
y_list = []
z_list = []

x_log = open('x.txt')
for line in x_log:
    line = line.rstrip()
    if 'error' in line and line not in x_list:
        x_list.append(line)
        print('ERROR-X',line)

y_log = open('y.txt')
for line in y_log:
    line = line.rstrip()
    if 'error' in line and line not in y_list:
        y_list.append(line)
        print('ERROR-Y',line)

z_log = open('z.txt')
for line in z_log:
    line = line.rstrip()
    if 'error' in line and line not in z_list:
        z_list.append(line)
        print('ERROR-Z',line)

it does what i need but i still need to run it in a loop, can anyone help me?

UPDATE2: managed to get it to work in a loop, if a new line is added and it meets the parsing parameters it will be printed.

code:

x_list = []
y_list = []
z_list = []
t = 1

while t == 1:
    x_log = open('x.txt','r')
    for line in x_log:
        line = line.rstrip()
        if 'error' in line and line not in x_list:
            x_list.append(line)
            print('ERROR-X',line)

    y_log = open('y.txt','r')
    for line in y_log:
        line = line.rstrip()
        if 'error' in line and line not in y_list:
            y_list.append(line)
            print('ERROR-Y',line)

    z_log = open('z.txt','r')
    for line in z_log:
        line = line.rstrip()
        if 'error' in line and line not in z_list:
            z_list.append(line)
            print('ERROR-Z',line)

Answer 1

The optimized approach:

def get_error_lines(fp, lines_set, suffix=''):
    ''' fp - file pointer; 
        lines_set - a set of unique error lines; 
        sufix - ERROR number(suffix) '''

    for line in fp:
        line = line.rstrip()
        if 'error' in line and line not in lines_set:
            lines_set.add(line)
            print('ERROR' + suffix, line)

# using set objects to hold unique items
x_set = set()
y_set = set()
z_set = set()

with open('x.txt', 'r') as x_log, open('y.txt', 'r') as y_log, open('z.txt', 'r') as z_log:
    get_error_lines(x_log, x_set, '1')
    get_error_lines(y_log, y_set, '2')
    get_error_lines(z_log, z_set, '3')