Questions tagged [string-concatenation]
String concatenation is the operation of joining two character strings end-to-end.
2,043
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How to concatenate string variables in Bash
In PHP, strings are concatenated together as follows:
$foo = "Hello";
$foo .= " World";
Here, $foo becomes "Hello World".
How is this accomplished in Bash?
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How to concatenate text from multiple rows into a single text string in SQL Server
Consider a database table holding names, with three rows:
Peter
Paul
Mary
Is there an easy way to turn this into a single string of Peter, Paul, Mary?
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answers
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Shortcuts in Objective-C to concatenate NSStrings
Are there any shortcuts to (stringByAppendingString:) string concatenation in Objective-C, or shortcuts for working with NSString in general?
For example, I'd like to make:
NSString *myString = @"...
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votes
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answers
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How to efficiently concatenate strings in go
In Go, a string is a primitive type, which means it is read-only, and every manipulation of it will create a new string.
So if I want to concatenate strings many times without knowing the length of ...
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Combine two columns of text in pandas dataframe
I have a dataframe that looks like
Year quarter
2000 q2
2001 q3
How do I add a new column by combining these columns to get the following dataframe?
Year quarter period
2000 q2 ...
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votes
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answers
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How do I concatenate strings and variables in PowerShell?
Suppose I have the following snippet:
$assoc = New-Object PSObject -Property @{
Id = 42
Name = "Slim Shady"
Owner = "Eminem"
}
Write-Host $assoc.Id + " - " ...
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answers
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How do I concatenate strings?
How do I concatenate the following combinations of types:
str and str
String and str
String and String
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answers
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How to concatenate strings in twig
Anyone knows how to concatenate strings in twig? I want to do something like:
{{ concat('http://', app.request.host) }}
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votes
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answers
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How to use GROUP BY to concatenate strings in SQL Server?
How do I get:
id Name Value
1 A 4
1 B 8
2 C 9
to
id Column
1 A:4, B:8
2 C:9
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475
votes
12
answers
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How can two strings be concatenated?
How can I concatenate (merge, combine) two values?
For example I have:
tmp = cbind("GAD", "AB")
tmp
# [,1] [,2]
# [1,] "GAD" "AB"
My goal is to concatenate the two values in "tmp" to one ...
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votes
16
answers
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How to keep the spaces at the end and/or at the beginning of a String?
I have to concatenate these two strings from my resource/value files:
<string name="Toast_Memory_GameWon_part1">you found ALL PAIRS ! on </string>
<string name="...
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votes
17
answers
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views
Using LINQ to concatenate strings
What is the most efficient way to write the old-school:
StringBuilder sb = new StringBuilder();
if (strings.Count > 0)
{
foreach (string s in strings)
{
sb.Append(s + ", ");
}
...
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404
votes
16
answers
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String concatenation in Ruby
I am looking for a more elegant way of concatenating strings in Ruby.
I have the following line:
source = "#{ROOT_DIR}/" << project << "/App.config"
Is there a nicer way of doing this?
...
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293
votes
7
answers
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views
How to set the id attribute of a HTML element dynamically with angularjs (1.x)?
Provided an HTML element of type div, how to set the value of its id attribute, which is the concatenation of a scope variable and a string ?
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votes
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answers
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C++ equivalent of StringBuffer/StringBuilder?
Is there a C++ Standard Template Library class that provides efficient string concatenation functionality, similar to C#'s StringBuilder or Java's StringBuffer?
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votes
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answers
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How to concatenate strings with padding in sqlite
I have three columns in an sqlite table:
Column1 Column2 Column3
A 1 1
A 1 2
A 12 2
C 13 2
B ...
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votes
13
answers
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How to create a SQL Server function to "join" multiple rows from a subquery into a single delimited field? [duplicate]
To illustrate, assume that I have two tables as follows:
VehicleID Name
1 Chuck
2 Larry
LocationID VehicleID City
1 1 New York
2 1 Seattle
3 ...
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answers
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How do I concatenate strings in Swift?
How to concatenate string in Swift?
In Objective-C we do like
NSString *string = @"Swift";
NSString *resultStr = [string stringByAppendingString:@" is a new Programming Language"];
or
NSString *...
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votes
16
answers
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Can I use require("path").join to safely concatenate urls?
Is this safe to use require("path").join to concatenate URLs, for example:
require("path").join("http://example.com", "ok");
//returns 'http://example.com/ok'
require("path").join("http://example....
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votes
15
answers
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Android TextView : "Do not concatenate text displayed with setText"
I am setting text using setText() by following way.
prodNameView.setText("" + name);
prodOriginalPriceView.setText("" + String.format(getString(R.string.string_product_rate_with_ruppe_sign), "" + ...
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votes
6
answers
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views
What is the string concatenation operator in Oracle?
What is the string concatenation operator in Oracle SQL?
Are there any "interesting" features I should be careful of?
(This seems obvious, but I couldn't find a previous question asking it).
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votes
5
answers
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Concatenating null strings in Java [duplicate]
Why does the following work? I would expect a NullPointerException to be thrown.
String s = null;
s = s + "hello";
System.out.println(s); // prints "nullhello"
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votes
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answers
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Concatenating string and integer in Python
In Python say you have
s = "string"
i = 0
print s + i
will give you error, so you write
print s + str(i)
to not get error.
I think this is quite a clumsy way to handle int and string ...
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votes
7
answers
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views
How do you append to an already existing string?
I want append to a string so that every time I loop over it, it will add "test" to the string.
Like in PHP you would do:
$teststr = "test1\n"
$teststr .= "test2\n"
echo = ...
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votes
13
answers
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const char* concatenation
I need to concatenate two const chars like these:
const char *one = "Hello ";
const char *two = "World";
How might I go about doing that?
I am passed these char*s from a third-party library with a ...
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votes
8
answers
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views
Optimal way to concatenate/aggregate strings
I'm finding a way to aggregate strings from different rows into a single row. I'm looking to do this in many different places, so having a function to facilitate this would be nice. I've tried ...
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votes
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answers
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Any reason not to use '+' to concatenate two strings? [duplicate]
A common antipattern in Python is to concatenate a sequence of strings using + in a loop. This is bad because the Python interpreter has to create a new string object for each iteration, and it ends ...
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votes
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answers
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Why is string concatenation faster than array join?
Today, I read this thread about the speed of string concatenation.
Surprisingly, string concatenation was the winner:
http://jsben.ch/#/OJ3vo
The result was opposite of what I thought. Besides, ...
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votes
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answers
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views
How is String concatenation implemented in Java 9?
As written in JEP 280: Indify String Concatenation:
Change the static String-concatenation bytecode sequence generated by javac to use invokedynamic calls to JDK library functions. This will enable ...
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votes
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answers
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SQL NVARCHAR and VARCHAR Limits
All, I have a large (unavoidable) dynamic SQL query. Due to the number of fields in the selection criteria the string containing the dynamic SQL is growing over 4000 chars. Now, I understand that ...
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votes
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answers
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views
Is the time-complexity of iterative string append actually O(n^2), or O(n)?
I am working on a problem out of CTCI.
The third problem of chapter 1 has you take a string such as
'Mr John Smith '
and asks you to replace the intermediary spaces with %20:
'Mr%20John%...
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votes
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answers
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String concatenation with Groovy
What is the best (idiomatic) way to concatenate Strings in Groovy?
Option 1:
calculateAccountNumber(bank, branch, checkDigit, account) {
bank + branch + checkDigit + account
}
Option 2:
...
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104
votes
7
answers
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views
JavaScript String concatenation behavior with null or undefined values
As you may know, in JavaScript '' + null = "null" and '' + undefined = "undefined" (in most browsers I can test: Firefox, Chrome and IE). I would like to know the origin of this oddity (what the heck ...
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views
If Python strings are immutable, why does it keep the same id if I use += to append to it?
Strings in Python are immutable, which means the value cannot be changed. However, when appending to the string in the following example, it looks like the original string memory is modified since the ...
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votes
10
answers
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views
SQL Server String Concatenation with Null
I am creating a computed column across fields of which some are potentially null.
The problem is that if any of those fields is null, the entire computed column will be null. I understand from the ...
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votes
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answers
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String concatenation vs. string substitution in Python
In Python, the where and when of using string concatenation versus string substitution eludes me. As the string concatenation has seen large boosts in performance, is this (becoming more) a stylistic ...
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votes
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answers
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How slow is Python's string concatenation vs. str.join?
As a result of the comments in my answer on this thread, I wanted to know what the speed difference is between the += operator and ''.join()
So what is the speed comparison between the two?
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answer
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views
How can I concatenate str and int objects?
If I try to do the following:
things = 5
print("You have " + things + " things.")
I get the following error in Python 3.x:
Traceback (most recent call last):
File "<...
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90
votes
9
answers
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views
Best practices/performance: mixing StringBuilder.append with String.concat
I'm trying to understand what the best practice is and why for concatenating string literals and variables for different cases. For instance, if I have code like this
StringBuilder sb = new ...
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6
answers
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golang convert "type []string" to string
I see some people create a for loop and run through the slice as to create a string, is there an easier way to convert a []string to a string?
Will sprintf do it?
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votes
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String concatenation without '+' operator
I was playing with python and I realized we don't need to use '+' operator to concatenate static strings. But it fails if I assign it to a variable.
For example:
string1 = 'Hello' 'World' #1 works ...
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votes
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answers
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String concatenation vs. interpolation in Ruby
I am just starting to learn Ruby (first time programming), and have a basic syntactical question with regards to variables, and various ways of writing code.
Chris Pine's "Learn to Program" taught ...
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Concatenating strings doesn't work as expected [closed]
I know it is a common issue, but looking for references and other material I don't find a clear answer to this question.
Consider the following code:
#include <string>
// ...
// in a method
...
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votes
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answers
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Getting strings recognized as variable names in R
Related: Strings as variable references in R
Possibly related: Concatenate expressions to subset a dataframe
I've simplified the question per the comment request. Here goes with some example data.
...
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votes
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answers
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views
How to concatenate strings in a Windows batch file?
I have a directory for which I want to list all the .doc files with a ;.
I know the following batch command echos all the files:
for /r %%i In (*.doc) DO echo %%i
But now I want to put them all in ...
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votes
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How do I concatenate two strings in Java?
I am trying to concatenate strings in Java. Why isn't this working?
public class StackOverflowTest {
public static void main(String args[]) {
int theNumber = 42;
System.out....
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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 = '...
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votes
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Create a comma-separated strings in C#
I have an object which holds many values, and some of them (not all values from the object) need to be put in a CSV string. My approach was this:
string csvString = o.number + "," + o.id + &...
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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=...
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votes
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How to construct a std::string from a std::vector<string>?
I'd like to build a std::string from a std::vector<std::string>.
I could use std::stringsteam, but imagine there is a shorter way:
std::string string_from_vector(const std::vector<std::...
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