Python - remove specific line in string variable-CodePudding

Is it possible in Python to remove only single line from a string variable without doing the concatenation of both chunks? I'm after removing cachedLength line.

input_columns = f'''\
<inputColumn 
    refId="Package\DFT\DST.Inputs[DST Input].Columns[{tbl}]"
    cachedDataType="{dt_type}"
    cachedName="{tbl}"
    cachedLength="{dt_lngh}"
    cachedPrecision="{dt_prc}"
    cachedScale="{dt_scl}"
    externalMetadataColumnId="Package\DFT\DST.Inputs[DST Input].ExternalColumns[{tbl}]"
    lineageId="Package\DFT\SRC.Outputs[SRC Output].Columns[{tbl}]" />
'''

Work in progress:

i = input_columns.split("\n")[4]
print(input_columns.replace(i, ""))

CodePudding user response：

You can replace the line using re module:

re.sub(r'\s*cachedLength=".*"', '', input_columns)

But as mentioned in the comments, technically, Python will recreate the string because it's an immutable type.

CodePudding user response：

Not exactly answering the question, but if modifying the xml is what you're after, you could use a package for that. E.g., using lxml:

xml = """\
<inputColumn 
    refId="Package\DFT\DST.Inputs[DST Input].Columns[{tbl}]"
    cachedDataType="{dt_type}"
    cachedName="{tbl}"
    cachedLength="{dt_lngh}"
    cachedPrecision="{dt_prc}"
    cachedScale="{dt_scl}"
    externalMetadataColumnId="Package\DFT\DST.Inputs[DST Input].ExternalColumns[{tbl}]"
    lineageId="Package\DFT\SRC.Outputs[SRC Output].Columns[{tbl}]" />
"""

e = etree.fromstring(xml)

del e.attrib["cachedLength"]

print(etree.tostring(e, pretty_print=True, encoding="unicode"))