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Questions tagged [string-concatenation]

String concatenation is the operation of joining two character strings end-to-end.

In particular in the theory of computation, the concatenation operation on strings is generalized to an operation on sets of strings as follows:

For two sets of strings S1 and S2, the concatenation S1S2 consists of all strings of the form vw where v is a string from S1 and w is a string from S2. In this definition, the string vw is the ordinary concatenation of strings v and w as defined in the introductory section. In this context, sets of strings are often referred to as formal languages.

Programming languages often provide operators (such as the + sign) to simplify concatenation of strings. For example, "s1" + "s2" would result in "s1s2".

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Is python += string concatenation bad practice?

I am reading The Hitchhiker’s Guide to Python and there is a short code snippet foo = 'foo' bar = 'bar' foobar = foo + bar # This is good foo += 'ooo' # This is bad, instead you should do: foo = ''.join([foo, 'ooo']) The author pointed out that…
nos
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How to collapse a list of characters into a single string in R

There is a list which I would like to output into an excel file as a single string. I start with a list of characters. url="http://eutils.ncbi.nlm.nih.gov/entrez/eutils/efetch.fcgi?db=pubmed&id=21558518&retmode=xml" xml =…
userJT
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Efficiently repeat a character/string n times in Scala

I would like to do the following more efficiently: def repeatChar(char:Char, n: Int) = List.fill(n)(char).mkString def repeatString(char:String, n: Int) = List.fill(n)(char).mkString repeatChar('a',3) // res0: String = aaa repeatString("abc",3)…
TimY
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How to construct a std::string from a std::vector?

I'd like to build a std::string from a std::vector. I could use std::stringsteam, but imagine there is a shorter way: std::string string_from_vector(const std::vector &pieces) { std::stringstream ss; …
WilliamKF
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Ternary operator and string concatenation quirk?

Hi I just want to know why this code yields (at least for me) an incorrect result. Well, probably i'm in fault here $description = 'Paper: ' . ($paperType == 'bond') ? 'Bond' : 'Other'; I was guessing that if paperType equals 'Bond' then…
Cesar
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Why to use StringBuffer in Java instead of the string concatenation operator

Someone told me it's more efficient to use StringBuffer to concatenate strings in Java than to use the + operator for Strings. What happens under the hood when you do that? What does StringBuffer do differently?
harry
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PHP string concatenation

Is it possible to concatenate strings, as follows? And if not, what is the alternative of doing so? while ($personCount < 10) { $result += $personCount . "person "; } echo $result; It should appear like 1 person 2 person 3 person, etc. You…
Illep
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Ampersand vs plus for concatenating strings in VB.NET

In VB.NET, is there any advantage to using & to concatenate strings instead of +? For example Dim x as String = "hello" + " there" vs. Dim x as String = "hello" & " there" Yes, I know for a lot of string concatenations I'd want to use…
dcp
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Adding quotes to a string in VBScript

I have this code: a = "xyz" g = "abcd " & a After running it, the value of g is abcd xyz. However, I want quotes around the value of a in g. After running the code, g should be abcd "xyz" instead. How can I accomplish this?
sushant
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Concatenation of Strings and characters

The following statements, String string = "string"; string = string +((char)65) + 5; System.out.println(string); Produce the output stringA5. The following however, String string = "string"; string += ((char)65) +…
Tiny
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How do you concatenate strings in a Puppet .pp file?

Here is my naive approach: # puppet/init.pp $x = 'hello ' + 'goodbye' This does not work. How does one concatenate strings in Puppet?
rlandster
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Concatenating variables in Bash

I am trying to add a variable to the middle of a variable, so for instance in PHP I would do this: $mystring = $arg1 . '12' . $arg2 . 'endoffile'; so the output might be 20121201endoffile, how can I achieve the same in a linux bash script?
Dan Hall
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Concat strings in a shell script

How can I concat strings in shell? Is it just... var = 'my'; var .= 'string'; ?
Ben
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How to concatenate a fixed string and a variable in Python

I want to include a file name, 'main.txt', in the subject. For that I am passing a file name from the command line. But I get an error in doing so: python sample.py main.txt # Running 'python' with an argument msg['Subject'] = "Auto Hella Restart…
Shivam Agrawal
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Making a string concatenation operator in R

I was wondering how one might go about writing a string concatenation operator in R, something like || in SAS, + in Java/C# or & in Visual Basic. The easiest way would be to create a special operator using %, like `%+%` <- function(a, b) paste(a, b,…
Hong Ooi
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