readlines with line number support?

[Nikhil]

Hi,

I am reading a file with readlines method of the filepointer object
returned by the open function. Along with reading the lines, I also need
to know which line number of the file is read in the loop everytime.
I am sure, the line should have the property/attribute which will say
the line number of the file.

If there is none, do I have to end up using the counter in the loop?

fp = open("file", "r")
lineno = 0
for line in fp.readlines():
print "line number: " + lineno + ": " + line.rstrip()
lineno = lineno + 1

 

[Paul McNett]

I am reading a file with readlines method of the filepointer object
returned by the open function. Along with reading the lines, I also need
to know which line number of the file is read in the loop everytime.
I am sure, the line should have the property/attribute which will say
the line number of the file.

If there is none, do I have to end up using the counter in the loop?

fp = open("file", "r")
lineno = 0
for line in fp.readlines():
print "line number: " + lineno + ": " + line.rstrip()
lineno = lineno + 1

Untested:

for lineno, line in enumerate(open("file")):
print "line number: %s : %s" % (idx, line.rstrip())

Note the other stylistic changes, too.


HTH.
Paul

 

[Arnaud Delobelle]

Hi,

I am reading a file with readlines method of the filepointer object
returned by the open function. Along with reading the lines, I also
need to know which line number of the file is read in the loop
everytime.
I am sure, the line should have the property/attribute which will say
the line number of the file.

If there is none, do I have to end up using the counter in the loop?

fp = open("file", "r")
lineno = 0
for line in fp.readlines():
print "line number: " + lineno + ": " + line.rstrip()
lineno = lineno + 1

The standard Python way is using enumerate()

for i, line in enumerate(fp):
print "line number: " + lineno + ": " + line.rstrip()

 

[Nikhil]

The standard Python way is using enumerate()

for i, line in enumerate(fp):
print "line number: " + lineno + ": " + line.rstrip()

Oh I did not know enumerate can be used. Thanks Paul and Arnaud.
I will try this.

 

[Nikhil]

The standard Python way is using enumerate()

for i, line in enumerate(fp):
print "line number: " + lineno + ": " + line.rstrip()

Oh I did not know enumerate can be used. Thanks Paul and Arnaud.
I will try this.

 

[Nikhil]

The standard Python way is using enumerate()

for i, line in enumerate(fp):
print "line number: " + lineno + ": " + line.rstrip()

I guess you meant to say :

for lineno, line in enumerate(fp):
print "line number: " + lineno + ": " + line.rstrip()

Thanks.

 

[Arnaud Delobelle]

I guess you meant to say :

for lineno, line in enumerate(fp):
print "line number: " + lineno + ": " + line.rstrip()

Yes!

 

[python]

Arnaud,

I suppose you could redefine enumerate to support an optional argument:

from itertools import izip, count

def enumerate(iterable, start=0):
return izip(count(start), iterable)
[(1, 's'), (2, 'p'), (3, 'a'), (4, 'm')]

Brilliant!!

Thank you,
Malcolm