CODEWITHSUNDEEP
python
Steve
Steve

Reputation: 347

Python3: Printing a block after finding a matched line

From the following file, I'd like to extract only the names belonging to the 'Family2'.

For example,

key1 = 'Family'

key2 = '2'

so that I could get James, Emily, and Judy only.

Family1:
  name: John
  name: Rachel
  name: Cindy
  name: William

Family2:
  name: James
  name: Emily
  name: Judy

Family3:
  name: Steve
  name: Olivia
  name: Noah
  name: William

Family4:
  name: Rachel

Family5:
  name: Mason

I could get up to the following.

key1 = 'Family'
key2 = '2'

found = False

matchedlines = []

with open('families.txt', 'r') as f:
  for line in f:
    if found == False:
      if key1 in line and key2 in line:
        found = True
    else:
      if key1 not in line:
        matchedlines.append(line)
      else:
        found = False

print(matchedlines)

Output:

['  name: James\n', '  name: Emily\n', '  name: Judy\n']

I think my logic is ok but any advice on making this neater or more Pythonic would be appreciated.

Thanks in advance.

Upvotes: 0

Views: 46

Answers (1)

alani
alani

Reputation: 13079

Some rather minor comments.

  • No need for if found == False - it only ever contains a boolean so you can just use if not found

  • When checking for the start line, you probably want to test in such a way as to exclude e.g. Family12:

  • You can make use of elif instead of having an else block that just contains an if block -- an if statement can have any number of elif blocks and then an optional else block.

  • You are probably going to want to extract the names from the matched lines, after checking that they actually contain names (your code includes the blank line in the matched lines). The code below contains a suggestion for how to do that simply.

  • at the end of the Family2 section, instead of setting found = False, you could just break from the loop entirely rather than bothering to process the rest of the file

  • four spaces per indentation level is probably more readable than 2 (used by PEP8 style guide)

key1 = 'Family'
key2 = '2'
key3 = 'name:'

found = False

names = []

with open('families.txt', 'r') as f:
    for line in f:
        if not found:
            if key1 + key2 + ":" in line:
                found = True
        elif key1 in line:
            break
        elif key3 in line:
            name = line.replace(key3, "").strip()
            names.append(name)

print(names)

Upvotes: 1

Related Questions