Fastest Way to Delete a Line from Large File in Python

Question

I am working with a very large (~11GB) text file on a Linux system. I am running it through a program which is checking the file for errors. Once an error is found, I need

Answer 1

I will provide two alternatives based on the look-up factor (line number or a search string):

Line number

def removeLine2(filename, lineNumber):
    with open(filename, 'r+') as outputFile:
        with open(filename, 'r') as inputFile:

            currentLineNumber = 0 
            while currentLineNumber < lineNumber:
                inputFile.readline()
                currentLineNumber += 1

            seekPosition = inputFile.tell()
            outputFile.seek(seekPosition, 0)

            inputFile.readline()

            currentLine = inputFile.readline()
            while currentLine:
                outputFile.writelines(currentLine)
                currentLine = inputFile.readline()

        outputFile.truncate()

String

def removeLine(filename, key):
    with open(filename, 'r+') as outputFile:
        with open(filename, 'r') as inputFile:
            seekPosition = 0 
            currentLine = inputFile.readline()
            while not currentLine.strip().startswith('"%s"' % key):
                seekPosition = inputFile.tell()
                currentLine = inputFile.readline()

            outputFile.seek(seekPosition, 0)

            currentLine = inputFile.readline()
            while currentLine:
                outputFile.writelines(currentLine)
                currentLine = inputFile.readline()

        outputFile.truncate()