python : join() called with 2 arguments in list comprehension?

Question

I am new to python. This code is from "Dive Into Python" by Mark Pilgrim, it appears that join() is being called with 2 args, it works fine:

dirname="/usr/"
[f for f in os.listdir(dirname) if os.path.isdir(os.path.join(dirname,f))]

But if you try:

smthn="data"
smthnelse="otherdata"
print "\n".join(smthn,smthnelse)

We get an error that join() can take only one argument.

one is str.join(), the other is from os module, have a look here http://stackoverflow.com/questions/1945920/os-path-join-python — Padraic Cunningham, May 04 '14 at 19:11

score 4 · Answer 1 · answered May 04 '14 at 19:11

4

os.path.join takes as arguments an arbitrary number of strings, str.join instead takes as one argument a iterable providing strings. These two functions are individual functions.

answered May 04 '14 at 19:11

Daniel

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saudi_Dev · Answer 2 · 2014-05-04T19:37:08.653

0

Look Using str.join() like this:

smthn="data"
smthnelse="otherdata"

print( "\n",smthn.join(smthnelse) )

Because you are put smthnelse between the spaces in smthn >>"data"

os.path.join() not look like str.join

the second for string and seq and the first only for File System paths.

edited May 04 '14 at 19:37

answered May 04 '14 at 19:28

saudi_Dev

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python : join() called with 2 arguments in list comprehension?

2 Answers2