Consider this Python code for printing a list of comma separated values
for element in list:
print element + ",",
What is the preferred method for printing such that a comma does not appear if element
is the final element in the list.
ex
开发者_运维百科a = [1, 2, 3]
for element in a
print str(element) +",",
output
1,2,3,
desired
1,2,3
>>> ','.join(map(str,a))
'1,2,3'
A ','.join
as suggested in other answers is the typical Python solution; the normal approach, which peculiarly I don't see in any of the answers so far, is
print ','.join(str(x) for x in a)
known as a generator expression or genexp.
If you prefer a loop (or need one for other purposes, if you're doing more than just printing on each item, for example), there are of course also excellent alternatives:
for i, x in enumerate(a):
if i: print ',' + str(x),
else: print str(x),
this is a first-time switch (works for any iterable a, whether a list or otherwise) so it places the comma before each item but the first. A last-time switch is slightly less elegant and it work only for iterables which have a len()
(not for completely general ones):
for i, x in enumerate(a):
if i == len(a) - 1: print str(x)
else: print str(x) + ',',
this example also takes advantage of the last-time switch to terminate the line when it's printing the very last item.
The enumerate built-in function is very often useful, and well worth keeping in mind!
It's very easy:
print(*a, sep=',')
Print lists in Python (4 Different Ways)
There are two options ,
You can directly print the answer using
print(*a, sep=',')
this will use separator as "," you will get the answer as ,
1,2,3
and another option is ,
print(','.join(str(x) for x in list(a)))
this will iterate the list and print the (a) and print the output as
1,2,3
That's what join
is for.
','.join([str(elem) for elem in a])
print ','.join(a)
def stringTokenizer(sentense,delimiters):
list=[]
word=""
isInWord=False
for ch in sentense:
if ch in delimiters:
if isInWord: # start ow word
print(word)
list.append(word)
isInWord=False
else:
if not isInWord: # end of word
word=""
isInWord=True
word=word+ch
if isInWord: # end of word at end of sentence
print(word)
list.append(word)
isInWord=False
return list
print (stringTokenizer(u"привет парни! я вам стихами, может быть, еще отвечу",", !"))
>>> a=[1,2,3]
>>> a=[str(i) for i in a ]
>>> s=a[0]
>>> for i in a[1:-1]: s="%s,%s"%(s,i)
...
>>> s=s+","+a[-1]
>>> s
'1,2,3'
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