Python: Append new line of string in specific line in the hierarchical structured text file

Question

For example the content in text file is like this:

Component_X
   Value1
      Value1.1

      Value1.2
      #Here is where i want to append the new string#

      Value1.3

   Value2
      Value2.1

      Value2.2

      Value2.3

Component_Y
   Value1
      Value1.1

      Value1.2

      Value1.3

   Value2
      Value2.1

      Value2.2

      Value2.3

Component_X
   Value1
      Value1.1

      Value1.2
      #Here is where i want to append the new string#

      Value1.3

   Value2
      Value2.1

      Value2.2

      Value2.3

My question is, how can I append a new string at the specific component such as I want to append new string in the Value1.2 of Value1 of the Component_X by using Python? Hopefully anybody can help this out.

My expected output after write the new string into the text file is:

Component_X
   Value1
      Value1.1

      Value1.2
      true

      Value1.3

   Value2
      Value2.1

      Value2.2

      Value2.3

Component_Y
   Value1
      Value1.1

      Value1.2

      Value1.3

   Value2
      Value2.1

      Value2.2

      Value2.3

Component_X
   Value1
      Value1.1

      Value1.2
      true

      Value1.3

   Value2
      Value2.1

      Value2.2

      Value2.3

Asked By: Jacky

||

Source

Answer 1

You need to read the file one line at a time. You’ll need to build the content in a list. Search for the value that you want to insert after. Do the insert then rewrite the file.

def insert_after(filename, component, after_this, value):
    in_component = False
    with open(filename, 'r+') as text:
        out_lines = []
        for line in text.readlines():
            if not line[0].isspace():
                in_component = line.startswith(component)
            out_lines.append(line)
            if in_component and line.strip() == after_this:
                pad = ' ' * (len(line) - len(line.lstrip()))
                out_lines.append(f"{pad}{value}n")
        text.seek(0)
        text.writelines(out_lines)

insert_after('foo.txt', 'Component_X', 'Value1.2', 'true')

Answered By: Cobra

Answer 2

Basically the idea is to check last most nearest component if X or not, last element value is 1.2 or not.

Here, I am text lines as list, first find the all position of Component and keep it as dict, after that run another loop and check conditions 1.2 in lines[i-1]and X in pos[[l for l in list(pos.keys())if l<i-1][-1]]]

Code:

def appendTxt(Alpha, Num, Add):
    pos = {i:v for i,v in enumerate(lines) if 'Component'in v}
    [lines.insert(i,Add)  for i in range(1, len(lines)) if Num in lines[i-1] and Alpha in pos[[l for l in list(pos.keys())if l<i-1][-1]]]
    return lines

lines = list(open('./t1.txt', 'r'))
appendTxt('X', '1.2', 'true')

Output:

['Component_Xn',
 '   Value1n',
 '      Value1.1n',
 'n',
 '      Value1.2n',
 'true',
 'n',
 '      Value1.3n',
 'n',
 '   Value2n',
 '      Value2.1n',
 'n',
 '          Value2.2n',
 'n',
 '          Value2.3n',
 'n',
 'Component_Yn',
 '   Value1n',
 '      Value1.1n',
 'n',
 '      Value1.2n',
 'n',
 '      Value1.3n',
 'n',
 '   Value2n',
 '      Value2.1n',
 'n',
 '          Value2.2n',
 'n',
 '          Value2.3n',
 'n',
 'Component_Xn',
 '   Value1n',
 '      Value1.1n',
 'n',
 '      Value1.2n',
 'true',
 'n',
 '      Value1.3n',
 'n',
 '   Value2n',
 '      Value2.1n',
 'n',
 '          Value2.2n',
 'n',
 '          Value2.3']

Answered By: R. Baraiya

Python: Append new line of string in specific line in the hierarchical structured text file

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