如何在python中使用readlines读取文件时提取相同列表的不同索引

Question

file = open(file = r'moto.txt')
bscAlertLines = file.readlines()            
for alertLine in bscAlertLines:
        if "MAINS_FAIL (1)" in alertLine:
            inxAlert = bscAlertLines.index(alertLine)
            print(inxAlert)
            alertString = alertLine.split()
            print(alertString)

Output looks like this:

86
['EAS', '0', '0', '0', '17', 'FMIC', 'Untagged', '02-15-2020', 'MAINS_FAIL', '(1)']
194
['EAS', '0', '0', '0', '17', 'FMIC', 'Untagged', '03-24-2020', 'MAINS_FAIL', '(1)']
194
['EAS', '0', '0', '0', '17', 'FMIC', 'Untagged', '03-24-2020', 'MAINS_FAIL', '(1)']
243
['EAS', '0', '0', '0', '17', 'FMIC', 'Untagged', '03-22-2020', 'MAINS_FAIL', '(1)']
262
['EAS', '0', '0', '0', '17', 'FMIC', 'Untagged', '02-22-2020', 'MAINS_FAIL', '(1)']
194
['EAS', '0', '0', '0', '17', 'FMIC', 'Untagged', '03-24-2020', 'MAINS_FAIL', '(1)']
194
['EAS', '0', '0', '0', '17', 'FMIC', 'Untagged', '03-24-2020', 'MAINS_FAIL', '(1)']
194
['EAS', '0', '0', '0', '17', 'FMIC', 'Untagged', '03-24-2020', 'MAINS_FAIL', '(1)']

In this case, index 194 is repeated (as the content of lists is similar) but in the text file it is at different indexes like 285,322,400. How can i retrieve these. How can i retrieve the original indexes as in file

Answer 1

The index function will always return the first index the alertLine appears, and the enumerate function would do you a favor:

with open('moto.txt','r') as f:
    for i,line in enumerate(f):
        if "MAINS_FAIL (1)" in line:
            print(i,line.split(),sep='\n')

Answer 2

In simple terms, the index() method finds the given element in a list and returns its position.

If the same element is present more than once, the method returns the index of the first occurrence of the element.

code:

file = open(file = r'moto.txt')
index = 0
bscAlertLines = file.readlines()            
for alertLine in bscAlertLines:
    index++
    if "MAINS_FAIL (1)" in alertLine:
        print(index-1)
        alertString = alertLine.split()
        print(alertString)

Answer 3

from collections import defaultdict

arr = [
    ["a", 15, "x"],
    ["b", 15, "x"],
    ["a", 15, "x"],
    ["a", 10, "y"],
    ["b", 15, "x"],
    ["b", 15, "y"],
    ["a", 10, "y"]
]

hash_map = defaultdict(list)

for i, list_el in enumerate(arr):
    el = tuple(list_el)
    hash_map[el].append(i)

print(hash_map)

This gives:

{
  ('a', 15, 'x'): [0, 2], 
  ('b', 15, 'x'): [1, 4], 
  ('a', 10, 'y'): [3, 6], 
  ('b', 15, 'y'): [5]
}

Since lists are mutable and cannot be used as keys in dictionaries, I cast them to tuple's to be able to store it in a dictionary.