File1.txt :

File2.txt :

Expected output:

This is my code:

file1 = open ("file1.txt",'r')
file2 = open ("file2.txt",'r')

file1_lines=file1.readlines()
file2_lines=file2.readlines()
for j, line2 in enumerate (file2_lines):
  for i in range (0,3):
    if file1_lines[i] in line2:
      print(line2)

Seems like i cannot make it iterate, im a beginner in coding, please point out why my code doesnt not working. Thank you :)

CodePudding user response：

Since it's file1 that determines the order, that has to be the outer loop.

file1 = open ("file1.txt",'r')
file2 = open ("file2.txt",'r')

file1_lines=file1.readlines()
file2_lines=file2.readlines()
for line1 in file1_lines:
  for line2 in file2_lines:
    if line2.startswith(line1):
      print(line2)

CodePudding user response：

Solution 1

One way to solve this problem is to have an order table such as:

Then, for each model, we replace "Honda" with "00000000-", "Toyota" with "00000001-", then sorting will be easy.

import itertools

# Create `order`: A dictionary to transform text in a format suitable
# for sorting
counter = itertools.count()
with open("file1.txt") as stream:
    order = {key.strip(): f"{value:>08}-" for key, value in zip(stream, counter)}

# At this point, order looks something like:
# {'Honda': '00000000-',
#  'Toyota': '00000001-',
#  'BMW': '00000002-',
#  'Ford': '00000003-'}

def keyfunc(text):
    "Translate Honda778 to 00000000-778, good for sorting."
    for key, value in order.items():
        text = text.replace(key, value)
    return text

# Read a list of models and sort
with open("file2.txt") as stream:
    models = stream.read().splitlines()
models.sort(key=keyfunc)

# Output
for model in models:
    print(model)

The output:

Honda778
Toyota126
BMW99
Ford78x

Solution 2

In this solution, we will create a bucket: A dictionary {make: list of models}, that might look something like:

{'Honda': ['Honda778'],
 'Toyota': ['Toyota126'],
 'BMW': ['BMW99'],
 'Ford': ['Ford78x']}

Then it is a matter of going through each list and print.

def get_make(model):
    """Given Toyota126, returns Toyota."""
    for make in bucket:
        if make in model:
            return make
        
with open("file1.txt") as stream:
    bucket = {key.strip(): [] for key in stream}

with open("file2.txt") as stream:
    for model in stream:
        model = model.strip()
        bucket[get_make(model)].append(model)
                
# Output
for models in bucket.values():
    print("\n".join(models))

While these solutions are somewhat long, I value long, but descriptive solutions over short, cryptic ones. Please comment.