Is there a commas-in-between idiom?

[Ernesto García García]

Hi experts,

it's very common that I have a list and I want to print it with commas
in between. How do I do this in an easy manner, whithout having the
annoying comma in the end?

<code>

list = [1,2,3,4,5,6]

# the easy way
for element in list:
print element, ',',

print
# this is what I really want. is there some way better?
if (len(list) 0):
print list[0],
for element in list[1:]:
print ',', element,

</code>

Thx,
Ernesto

[Christian Joergensen]

Ernesto García García <ti************ **********@gmai l.comwrites:

Hi experts,

it's very common that I have a list and I want to print it with commas
in between. How do I do this in an easy manner, whithout having the
annoying comma in the end?

>>list = [1,2,3,4,5,6]
print ','.join(map(st r, list))

1,2,3,4,5,6

--
Christian Joergensen | Linux, programming or web consultancy
http://www.razor.dk | Visit us at: http://www.gmta.info

[Peter Otten]

Ernesto García García wrote:

it's very common that I have a list and I want to print it with commas
in between. How do I do this in an easy manner, whithout having the
annoying comma in the end?

>>items = [1, 2, 3, "many"]
print ", ".join(str(item ) for item in items)

1, 2, 3, many

Peter

[James Stroud]

Ernesto García García wrote:

Hi experts,

it's very common that I have a list and I want to print it with commas
in between. How do I do this in an easy manner, whithout having the
annoying comma in the end?

<code>

list = [1,2,3,4,5,6]

# the easy way
for element in list:
print element, ',',

print
# this is what I really want. is there some way better?
if (len(list) 0):
print list[0],
for element in list[1:]:
print ',', element,

</code>

Thx,
Ernesto

print ",".joint(some_ list)

Where what you have named "list" is now called "some_list" because it is
terribly ill-advised to reassign the name of a built-in type.

James

[Ernesto García García]

Ernesto García García wrote:

Hi experts,

it's very common that I have a list and I want to print it with commas
in between. How do I do this in an easy manner, whithout having the
annoying comma in the end?

<code>

list = [1,2,3,4,5,6]

# the easy way
for element in list:
print element, ',',

print
# this is what I really want. is there some way better?
if (len(list) 0):
print list[0],
for element in list[1:]:
print ',', element,

</code>

Thx,
Ernesto

mylist = [1,2,3,4,5,6]
print ','.join(map(st r, mylist))

Great solution!

Thank all of you,
Ernesto

[Tim Peters]

]Ernesto García García]

it's very common that I have a list and I want to print it with commas
in between. How do I do this in an easy manner, whithout having the
annoying comma in the end?

<code>

list = [1,2,3,4,5,6]

# the easy way
for element in list:
print element, ',',

print
# this is what I really want. is there some way better?
if (len(list) 0):

More idiomatic as

if len(list) 0:

and even more so as plain

if list:

print list[0],
for element in list[1:]:
print ',', element,

Do you really want a space before and after each inter-element comma?

</code>

An often-overlooked alternative to playing with ",".join() is:

print str(list)[1:-1]

That is, ask Python to change the list into a big string, and just
strip the brackets off each end:

>>alist = ['a, bc', 4, True]
print str(alist)[1:-1]

'a, bc', 4, True

Note the quotes around the string element! This differs from what
your code snippet above would produce (in addition to differing wrt
spaces around inter-element commas):

a, bc , 4 , True

[Ernesto García García]

Tim Peters wrote:

More idiomatic as

if len(list) 0:

and even more so as plain

if list:

> print list[0],
for element in list[1:]:
print ',', element,

Do you really want a space before and after each inter-element comma?

No, but it was only an example. I usually go for string concatenation.

An often-overlooked alternative to playing with ",".join() is:

print str(list)[1:-1]

That's funny! Not that I like it more that the join solution, but funny
nevertheless.

Thank you,
Ernesto

[Fredrik Lundh]

Ernesto García García wrote:

it's very common that I have a list and I want to print it with commas
in between. How do I do this in an easy manner, whithout having the
annoying comma in the end?

I've collected a bunch of list pydioms and other notes here:

http://effbot.org/zone/python-list.htm

For formatting issues, see:

http://effbot.org/zone/python-list.htm#printing

</F>

[Ernesto García García]

I've collected a bunch of list pydioms and other notes here:

>
http://effbot.org/zone/python-list.htm

Thank you for the suggestion.

Ernesto

[Peter van Kampen]

On 2006-11-06, Fredrik Lundh <fr*****@python ware.comwrote:

I've collected a bunch of list pydioms and other notes here:

http://effbot.org/zone/python-list.htm

"""
A = B = [] # both names will point to the same list
"""

I've been bitten by this once or twice in the past, but I have always
wondered what it was useful for? Can anybody enlighten me?

TIA,

PterK

--
Peter van Kampen
pterk -- at -- datatailors.com