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Questions tagged [concatenation]

Joining of two or more sequences into a single sequence.

Concatenation refers to the joining of two or more elements into a single element.

In programming, this can refer to

  • concatenation, which joins multiple strings into a single string
  • concatenation, where one or more arrays are combined (mostly appended) to make a new array
  • specific concatenation functions that combine elements along a specified dimension (horizontally, or vertically for example), replicate and tile existing elements, and so forth.
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String concatenation in MySQL

I am using MySQL and MySQL Workbench 5.2 CE. When I try to concatenate 2 columns, last_name and first_name, it doesn't work : select first_name + last_name as "Name" from test.student
Roshan
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MySQL CONCAT returns NULL if any field contain NULL

I have following data in my table "devices" affiliate_name affiliate_location model ip os_type os_version cs1 inter Dell 10.125.103.25 Linux Fedora cs2 inter …
Neeraj
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How do I concatenate text files in Python?

I have a list of 20 file names, like ['file1.txt', 'file2.txt', ...]. I want to write a Python script to concatenate these files into a new file. I could open each file by f = open(...), read line by line by calling f.readline(), and write each line…
JJ Beck
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How to concatenate columns in a Postgres SELECT?

I have two string columns a and b in a table foo. select a, b from foo returns values a and b. However, concatenation of a and b does not work. I tried : select a || b from foo and select a||', '||b from foo Update from comments: both columns…
Alex
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How do you concatenate Lists in C#?

If I have: List myList1; List myList2; myList1 = getMeAList(); // Checked myList1, it contains 4 strings myList2 = getMeAnotherList(); // Checked myList2, it contains 6 strings myList1.Concat(myList2); // Checked mylist1, it…
Matt
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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 *resultStr=[NSString stringWithFormat:@"%@ is a new…
Rajneesh071
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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), "" + new BigDecimal(price).setScale(2,…
Pratik Butani
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How do I combine two lists in Dart?

I was wondering if there was an easy way to concatenate two lists in dart to create a brand new list object. I couldn't find anything and something like this: My list: list1 = [1, 2, 3] list2 = [4, 5, 6] I tried: var newList = list1 + list2; I…
Alex
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SQL UPDATE all values in a field with appended string CONCAT not working

Here is what I want to do: current table: +----+-------------+ | id | data | +----+-------------+ | 1 | max | | 2 | linda | | 3 | sam | | 4 | henry | +----+-------------+ Mystery Query (…
Fresheyeball
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What is the best way to concatenate vectors in Rust?

Is it even possible to concatenate vectors in Rust? If so, is there an elegant way to do so? I have something like this: let mut a = vec![1, 2, 3]; let b = vec![4, 5, 6]; for val in &b { a.push(val); } Does anyone know of a better way?
Joe Thomas
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Include constant in string without concatenating

Is there a way in PHP to include a constant in a string without concatenating? define('MY_CONSTANT', 42); echo "This is my constant: MY_CONSTANT";
Brian
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Most efficient way to concatenate strings in JavaScript?

In JavaScript, I have a loop that has many iterations, and in each iteration, I am creating a huge string with many += operators. Is there a more efficient way to create a string? I was thinking about creating a dynamic array where I keep adding…
omega
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How do I concatenate multiple C++ strings on one line?

C# has a syntax feature where you can concatenate many data types together on 1 line. string s = new String(); s += "Hello world, " + myInt + niceToSeeYouString; s += someChar1 + interestingDecimal + someChar2; What would be the equivalent in C++?…
Nick Bolton
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Concatenating null strings in Java

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"
yavoh
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How can I concatenate twice with the C preprocessor and expand a macro as in "arg ## _ ## MACRO"?

I am trying to write a program where the names of some functions are dependent on the value of a certain macro variable with a macro like this: #define VARIABLE 3 #define NAME(fun) fun ## _ ## VARIABLE int NAME(some_function)(int…
JJ.
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