Get Line Number in file with Python

lookup = 'text to find'

with open(filename) as myFile:
    for num, line in enumerate(myFile, 1):
        if lookup in line:
            print('found at line:', num)

Or:

f = open('some_file.txt','r')
line_num = 0
search_phrase = "the dog barked"
for line in f.readlines():
    line_num += 1
    if line.find(search_phrase) >= 0:
        print(line_num)

Or:

def line_num_for_phrase_in_file(phrase='the dog barked', filename='file.txt')
    with open(filename,'r') as f:
        for (i, line) in enumerate(f):
            if phrase in line:
                return i
    return -1

Or:

lookup="The_String_You're_Searching"
file_name = open("file.txt")
for num, line in enumerate(file_name,1):
        if lookup in line:
            print(num)

Or:

f_rd = open(path, 'r')
file_lines = f_rd.readlines()
f_rd.close()

matches = [line for line in file_lines if "chars of Interest" in line]
index = file_lines.index(matches[0])