在文件中查找单词

Question

I'm trying to read from a file 'input.txt', one line at a time, numbering each line. I then need to check each line to see whether the letters in the line can be used to make the word 'aardvark'. Uppercase letters can be used as well and the letters can be spread throughout the line. The text file's contents are:

No aardv*rks here!

Only armadillos and anteaters.

Animals are run down: very awful road kill.

I prefer a quick guacamole made from avocados.

So line 3 and 4 only should return a positive, such as "Aardvark on line 3".

I've gotten this far - and I'm stuck!

file = open('input.txt').read().lower() 
listed = file.split('\n')  
for sentence in listed:
  a = sentence.count('a')
  r = sentence.count('r')
  d = sentence.count('d')
  v = sentence.count('v')
  k = sentence.count('k')
  if a==3 and r==2 and d==1 and v==1 and k==1:
    print('Aardvark on line '+listed[sentence])

Please understand that I'm working through beginner tutorials, so no wild and fancy functions that will blow my tiny, fragile mind, please!!

Many thanks in anticipation.

EDIT

This is the solution that finally worked. Many thanks for the contributions once again!

file = open('input.txt').read().lower() 
listed = file.split('\n')  
for index, sentence in enumerate(listed):
  a = sentence.count('a')
  r = sentence.count('r')
  d = sentence.count('d')
  v = sentence.count('v')
  k = sentence.count('k')
  if a>=3 and r>=2 and d>=1 and v>=1 and k>=1:
    print('Aardvark on line '+str(index+1))

Answer 1

open('input.txt').read() reads the entire content of the file into memory. Thus, if input.txt is a long enough file the computer will exhaust its available memory. Instead, try reading the lines one at a time using the file iterator, eg

for i,listed in enumerate(open('input.txt')):
    sentence = listed.lower()
    a = sentence.count('a')
    # ... etc.

See also In Python, why do we need readlines() when we can iterate over the file handle itself? .

Answer 2

for n, line in enumerate(open('input.txt')):
  letters = list('aardvark')
  for c in line.lower():
    if c in letters:
      letters.remove(c)
  if not letters:
    print('Aardvark on line', n + 1)

Answer 3

I know this is an old thread, but for those undertaking this task through Grok the following code uses only what has been taught so far in the course. Hope you find it useful!

count = 0
with open('input.txt') as f:
  for line in f:
    count += 1
    l = line.lower()
    a = l.count('a')
    d = l.count('d')
    k = l.count('k')
    r = l.count('r')
    v = l.count('v')
    if a >= 3 and d >= 1 and k >= 1 and r >=2 and v >=1:
      print('Aardvark on line', count)