How can strings be concatenated?

Question

How to concatenate strings in python?

For example:

Section = 'C_type'

Concatenate it with Sec_ to form the string:

Sec_C_type

score 184 · Accepted Answer · edited Apr 22 '18 at 01:52

184

The easiest way would be

Section = 'Sec_' + Section

But for efficiency, see: https://waymoot.org/home/python_string/

edited Apr 22 '18 at 01:52

Graham

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answered Apr 26 '10 at 06:59

mpen

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Actually it seems to have been optimized since the article you cite. From a quick test with timeit, I wasn't able to reproduce the results. – tonfa May 28 '11 at 15:05
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The OP asked for Python 2.4 but about version 2.7, Hatem Nassrat has tested (July 2013) [three concatenation techniques](http://leadsift.com/python-string-concatenation/) where `+` is faster when concatenating less than 15 strings but he recommends the other techniques: `join`and `%`. (this current comment is just to confirm the @tonfa's comment above). Cheers ;) – oHo Nov 12 '13 at 13:06
What happens if you want a multi line string concatenation? – pyCthon Nov 28 '13 at 19:52
@pyCthon: Huh? You can put a line break in a string using `\n` or you can do a line continuation in Python by putting a \ at the end of the line. – mpen Nov 28 '13 at 20:45

score 44 · Answer 2 · answered Apr 26 '10 at 07:04

44

you can also do this:

section = "C_type"
new_section = "Sec_%s" % section

This allows you not only append, but also insert wherever in the string:

section = "C_type"
new_section = "Sec_%s_blah" % section

answered Apr 26 '10 at 07:04

rytis

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This method also allows you to 'concat' an int to string, which isn't possible directly with `+` (requires wrapping the int in a `str()`) – aland Dec 08 '18 at 16:04

Juliusz · Answer 3 · 2017-09-20T08:43:07.797

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Just a comment, as someone may find it useful - you can concatenate more than one string in one go:

>>> a='rabbit'
>>> b='fox'
>>> print '%s and %s' %(a,b)
rabbit and fox

edited Sep 20 '17 at 08:43

answered Apr 11 '13 at 16:16

Juliusz

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score 24 · Answer 4 · edited Nov 12 '13 at 08:53

24

More efficient ways of concatenating strings are:

join():

Very efficent, but a bit hard to read.

>>> Section = 'C_type'  
>>> new_str = ''.join(['Sec_', Section]) # inserting a list of strings 
>>> print new_str 
>>> 'Sec_C_type'

String formatting:

Easy to read and in most cases faster than '+' concatenating

>>> Section = 'C_type'
>>> print 'Sec_%s' % Section
>>> 'Sec_C_type'

edited Nov 12 '13 at 08:53

avelis

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answered Dec 14 '12 at 15:03

j7nn7k

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Seems like join is the fastest and efficient too http://waymoot.org/home/python_string/ – enthusiasticgeek Jan 29 '15 at 04:12

score 6 · Answer 5 · answered Apr 26 '10 at 07:02

6

Use + for string concatenation as:

section = 'C_type'
new_section = 'Sec_' + section

answered Apr 26 '10 at 07:02

codaddict

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score 4 · Answer 6 · answered Apr 26 '10 at 07:01

4

To concatenate strings in python you use the "+" sign

ref: http://www.gidnetwork.com/b-40.html

answered Apr 26 '10 at 07:01

Steve Robillard

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score 2 · Answer 7 · answered Nov 06 '13 at 20:56

2

For cases of appending to end of existing string:

string = "Sec_"
string += "C_type"
print(string)

results in

Sec_C_type

answered Nov 06 '13 at 20:56

Tom Howard

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How can strings be concatenated?

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