I don't know how to express this. I want to print:
_1__2__3__4_
With "_%s_" as a substring of that. How to get the main string when I format the substring? (as a shortcut of:
for x in range(1,5):
print "_%s_" % (x)
(Even though this prints multiple lines))
Edit: just in one line
Did you mean something like this?
my_string = "".join(["_%d_" % i for i in xrange(1,5)])
That creates a list of the substrings as requested and then concatenates the items in the list using the empty string as separator (See str.join() documentation).
Alternatively you can add to a string though a loop with the += operator although it is much slower and less efficient:
s = ""
for x in range(1,5):
s += "_%d_" % x
print s
"_%s_" % i for i in range(1,5). Why do u use join to empty string?
join is a method on the str type - so you have to use it on some string. It's often used like ', '.join(items) -> foo, bar, baz as a very elegant way to deal with the fencepost problem, but just as well can be used with the empty string for easy way to concatenate items of a sequence.print("_" + "__".join(map(str, xrange(1,5)))) +"_"
_1__2__3__4_
In [9]: timeit ("_" + "__".join(map(str,xrange(1,5)))) +"_"
1000000 loops, best of 3: 1.38 µs per loop
In [10]: timeit "".join(["_%d_" % i for i in xrange(1,5)])
100000 loops, best of 3: 3.19 µs per loop
you can maintain your style if you want to.
if you are using python 2.7:
from __future__ import print_function
for x in range(1,5):
print("_%s_" % (x), sep = '', end = '')
print()
for python 3.x, import is not required.
python doc: https://docs.python.org/2.7/library/functions.html?highlight=print#print
Python 3:
print("_{}_".format("__".join(map(str,range(1,5)))))
_1__2__3__4_
Python 2:
print "_{0}_".format("__".join(map(str,range(1,5))))
_1__2__3__4_
"_" + s + "_"