[Q] How to ignore the first line of the text read from a file

[youngjin.michael]

Hello,

I am new to Python and have one simple question to which I cannot find
a satisfactory solution.
I want to read text line-by-line from a text file, but want to ignore
only the first line. I know how to do it in Java (Java has been my
primary language for the last couple of years) and following is what I
have in Python, but I don't like it and want to learn the better way
of doing it.

file = open(fileName, 'r')
lineNumber = 0
for line in file:
if lineNumber == 0:
lineNumber = lineNumber + 1
else:
lineNumber = lineNumber + 1
print line

Can anyone show me the better of doing this kind of task?

Thanks in advance.

[Marc 'BlackJack' Rintsch]

On Wed, 27 Aug 2008 21:11:26 -0700, yo************* *@gmail.com wrote:

I want to read text line-by-line from a text file, but want to ignore
only the first line. I know how to do it in Java (Java has been my
primary language for the last couple of years) and following is what I
have in Python, but I don't like it and want to learn the better way of
doing it.

file = open(fileName, 'r')
lineNumber = 0
for line in file:
if lineNumber == 0:
lineNumber = lineNumber + 1
else:
lineNumber = lineNumber + 1
print line

Can anyone show me the better of doing this kind of task?

input_file = open(filename)
lines = iter(input_file )
lines.next() # Skip line.
for line in lines:
print line
input_file.clos e()

Ciao,
Marc 'BlackJack' Rintsch

[Chris]

On Aug 28, 6:11*am, "youngjin.mich. [e-mail]"
<youngjin.mich. [e-mail] te:

Hello,

I am new to Python and have one simple question to which I cannot find
a satisfactory solution.
I want to read text line-by-line from a text file, but want to ignore
only the first line. I know how to do it in Java (Java has been my
primary language for the last couple of years) and following is what I
have in Python, but I don't like it and want to learn the better way
of doing it.

file = open(fileName, 'r')
lineNumber = 0
for line in file:
* * if lineNumber == 0:
* * * * lineNumber = lineNumber + 1
* * else:
* * * * lineNumber = lineNumber + 1
* * * * print line

Can anyone show me the better of doing this kind of task?

Thanks in advance.

fileInput = open(filename, 'r')
for lnNum, line in enumerate(fileI nput):
if not lnNum:
continue
print line

[Santiago Romero]

I want to read text line-by-line from a text file, but want to ignore

only the first line. I know how to do it in Java (Java has been my
primary language for the last couple of years) and following is what I
have in Python, but I don't like it and want to learn the better way
of doing it.

Why don't you read and discard the first line before processing the
rest of the file?

file = open(filename, 'r')
file.readline()
for line in file: print line,

(It works).

[Ken Starks]

yo************* *@gmail.com wrote:

Hello,

I am new to Python and have one simple question to which I cannot find
a satisfactory solution.
I want to read text line-by-line from a text file, but want to ignore
only the first line. I know how to do it in Java (Java has been my
primary language for the last couple of years) and following is what I
have in Python, but I don't like it and want to learn the better way
of doing it.

file = open(fileName, 'r')
lineNumber = 0
for line in file:
if lineNumber == 0:
lineNumber = lineNumber + 1
else:
lineNumber = lineNumber + 1
print line

Can anyone show me the better of doing this kind of task?

Thanks in advance.

LineList=open(f ilename,'r').re adlines()[1,]
for line in Linelist:
blah blah

[Paul Rubin]

Ken Starks <st*****@lampsa cos.demon.co.uk writes:

LineList=open(f ilename,'r').re adlines()[1,]

You don't want to do that if the file is very large. Also,
you meant [1:] rather than [1,]

[Chris]

On Aug 28, 11:53*am, Ken Starks <stra...@lampsa cos.demon.co.uk wrote:

youngjin.mich.. [e-mail] wrote:

Hello,

I am new to Python and have one simple question to which I cannot find
a satisfactory solution.
I want to read text line-by-line from a text file, but want to ignore
only the first line. I know how to do it in Java (Java has been my
primary language for the last couple of years) and following is what I
have in Python, but I don't like it and want to learn the better way
of doing it.

file = open(fileName, 'r')
lineNumber = 0
for line in file:
* * if lineNumber == 0:
* * * * lineNumber = lineNumber + 1
* * else:
* * * * lineNumber = lineNumber + 1
* * * * print line

Can anyone show me the better of doing this kind of task?

Thanks in advance.

LineList=open(f ilename,'r').re adlines()[1,]
for line in Linelist:
* * blah blah

That's bad practice as you load the entire file in memory first as
well as it will result in a type error (should be '.readlines()[1:]')

[rurpy]

On Aug 27, 11:12 pm, Marc 'BlackJack' Rintsch <[e-mail] wrote:

On Wed, 27 Aug 2008 21:11:26 -0700, youngjin.mich.. [e-mail] wrote:

I want to read text line-by-line from a text file, but want to ignore
only the first line. I know how to do it in Java (Java has been my
primary language for the last couple of years) and following is what I
have in Python, but I don't like it and want to learn the better way of
doing it.

file = open(fileName, 'r')
lineNumber = 0
for line in file:
if lineNumber == 0:
lineNumber = lineNumber + 1
else:
lineNumber = lineNumber + 1
print line

Can anyone show me the better of doing this kind of task?

input_file = open(filename)
lines = iter(input_file )
lines.next() # Skip line.
for line in lines:
print line
input_file.clos e()

Ciao,
Marc 'BlackJack' Rintsch

A file object is its own iterator so you can
do more simply:

input_file = open(filename)
input_file.next () # Skip line.
for line in input_file:
print line,
input_file.clos e()

Since the line read includes the terminating
EOL character(s), print it with a "print ... ,"
to avoid adding an additional EOL.

If the OP needs line numbers elsewhere in the
code something like the following would work.

infile = open(fileName, 'r')
for lineNumber, line in enumerate (infile):
# enumerate returns numbers starting with 0.
if lineNumber == 0: continue
print line,

[Paul Rubin]

ru***@yahoo.com writes:

If the OP needs line numbers elsewhere in the
code something like the following would work.

infile = open(fileName, 'r')
for lineNumber, line in enumerate (infile):
# enumerate returns numbers starting with 0.
if lineNumber == 0: continue
print line,

This also seems like a good time to mention (untested):

from itertools import islice

for line in islice(infile, 1, None):
print line,

[norseman]

Benjamin Kaplan wrote:

On Thu, Aug 28, 2008 at 12:11 AM, yo************* *@gmail.com <
yo************* *@gmail.comwrote:

>Hello,

I am new to Python and have one simple question to which I cannot find
a satisfactory solution.
I want to read text line-by-line from a text file, but want to ignore
only the first line. I know how to do it in Java (Java has been my
primary language for the last couple of years) and following is what I
have in Python, but I don't like it and want to learn the better way
of doing it.

file = open(fileName, 'r')
lineNumber = 0
for line in file:
if lineNumber == 0:
lineNumber = lineNumber + 1
else:
lineNumber = lineNumber + 1
print line

Can anyone show me the better of doing this kind of task?

Thanks in advance.

--

Files are iterators, and iterators can only go through the object once. Just
call next() before going in the for loop. Also, don't use "file" as a
variable name. It covers up the built-in type.

afile = open(file_name, 'r')
afile.next() #just reads the first line and doesn't do anything with it
for line in afile :
print line

>http://mail.python.org/mailman/listinfo/python-list

------------------------------------------------------------------------

--
http://mail.python.org/mailman/listinfo/python-list

=============== ===
actually:
import os

file = open(filename, 'r')
for line in file:
dummy=line
for line in file:
print line
is cleaner and faster.
If you need line numbers, pre-parse things, whatever, add where needed.

Steve
no******@hughes .net