[Tutor] Example for read and readlines() (Asad)

[Avi Gross]

Asad,

Like many projects, there may be many ways to do things BUT some rules do
apply.

You can only read an open file ONCE unless you seek back to the beginning or
reopen it.

string = f3.read()
string1 = f3.readlines()

The first line reads the entire file into a single buffer.

The second program line won't work as intended. The first consumed the
entire file.

Much of the rest is not organized well enough for me to understand what you
want to do. I find it important for people to try some simple things like
examining the values step by step. Had you typed

print (string)
print (string1)

on a small sample file, you might have fixed that before continuing. Then
each step along the way you could examine and verify it made sense up to
that point.

Try writing the outline of the logic of your program first in English or
your native language as an algorithm. Then see what tools are needed. Look
at a sample of the log you are evaluating and see what it takes to locate
the lines you want and then to break out the parts you want to keep for
further use. 

What I see looks like this:

If you find one instance of the string "ERR1"
Then 
You want to find ALL (nonoverlapping) regions consisting of an upper-case
letter followed by two lower-case letters and a space and either a space or
digits 1 to 3 and digits 0-9 and a space and ...

Fairly complex pattern.

But you are searching the contents of the ENTIRE file for this and since you
seem to have wanted to replace all newlines by spaces and your pattern
includes spaces, this would match something that wrapped around from line to
line. Is this what you wanted?

You then switch gears to using the readlines version and I decided to get
back to my regularly scheduled life. As noted, that probably is an empty
string or worse. Good luck.

-----Original Message-----
From: Tutor <tutor-bounces+avigross=verizon.net at python.org> On Behalf Of
Asad
Sent: Sunday, November 11, 2018 8:54 PM
To: tutor at python.org
Subject: Re: [Tutor] Example for read and readlines() (Asad)

Hi All ,

       Thanks for the reply . I am building a framework for the two error
conditions, therefore I need to read and readlines because in one only regex
is required and in other regex+ n-1 line is required to process :

#Here we are opening the file and substituting space " " for each \n
encountered
f3 = open  (r"D:\QI\log.log", 'r')
string = f3.read()
string1 = f3.readlines()
regex = re.compile ( "\n" )
st = regex.sub ( " ", string )

if re.search('ERR1',st):
    y=re.findall("[A-Z][a-z][a-z] [ 123][0-9]
[012][0-9]:[0-5][0-9]:[0-5][0-9] [0-9][0-9][0-9][0-9]",st)
    print y

patchnumber = re.compile(r'(\d+)\/(\d+)')                ======> doesnot
work it only works if I use  #string = f3.read() for j in
range(len(string1)):
    if re.search ( r'ERR2', string1[j] ):
        print "Error line \n", string1[j - 1]
        mo = patchnumber.search (string1[j-1])
        a = mo.group()
        print a
        print os.getcwd()
        break

Please advice how to proceed.

Thanks,