# Questions tagged [concatenation]

Questions on how to concatenate/join/merge lists/arrays of symbols/numbers/strings/etc. to obtain a given form of the output.

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### Simple way to concatenate Dataset columns

Consider these two datasets: d1 = Transpose@Dataset[<|"a" -> Range|>]; d2 = Transpose@Dataset[<|"b" -> Range[5, 1, -1]|>]; {d1, d2} What's ...
3answers
1k views

### How to build a matrix from a set of vectors and other matrices using ArrayFlatten

I want to build a 6 by 3 matrix, from the following: one vector is 3 by 1, then a matrix, which is 3 by 2. These will go to the top 3 rows. Now the bottom 3 rows, I'll have 3 vectors each is 3 by 1. ...
2answers
896 views

### How to name a variable with the value of another variable?

A simple but very important (at least for me) question. In some languages for defining a variable, for example, we can do: i=10 "d"&i=30 So I have defined the variable d10, and... d10=30 ...
4answers
725 views

### Concatenating strings, unevaluated expressions and evaluated expressions/values

Maybe this is something very simple to some of you. Anyway, I think this can be useful to many others like me. I would like to build an output that involves strings, unevaluated expressions and ...
3answers
399 views

### Convert a list to an integer

How can we convert a list to an integer correctly? {5, 22, 4, 5} -> 52245? When I use the command FromDigits in Mathematica ...
3answers
310 views

### How to 'merge' a list like FromDigits, but with a mixture of numbers and symbols?

How do I go from {C,4,G,5,S,7} to C4G5S7
3answers
2k views

### how to concatenate a list of a list of strings

I have two lists of lists, La and Lb that I want to concatenate so that every element of a list n in La is concatenated with the ...
7answers
4k views

### Getting a String from a list of strings

Is there a way to write down Mathematica with a string such as: {"M","a","t","h","e","m","a","t","i","c","a"}?
2answers
7k views

### Joining Together Strings and variables [closed]

I am trying to join together strings and variables as part of formatting the output of my code. For example how do I print the line "5 trees" where the number 5 is a variable n that could be changing. ...
3answers
411 views

### List of the combinations of more lists via permutations

I would like to generate a list of all the possible combinations of two lists. As for instance, given L=3; list={0,1,2}; I would like to obtain the list {{0,...
3answers
296 views

### How to join many tables side by side?

I have function for table $t$ t[n_] := Table[i*n, {i, 1, 3}]; For example t=(1, 2, 3), t=(2, 4, 6), and t=(3, 6, 9) To join $n=3$ tables side by side ...
2answers
105 views

### Obtaining all possible ways to concatenate matrices

With Prepend we can add a line to all matrices in a set, like this: ...
1answer
80 views

### What's the easiest way to combine specific columns of two matrices?

given matrices A = {{3, 10, 10, 5.}, {4, 10, 10, 6.}, {5, 10, 10, 7.}} B = {{6, 10, 10, 5.}, {7, 10, 10, 6.}, {8, 10, 10, 7.}} how can i get a matrix which ...
1answer
96 views

### Merge neighbour Lists in List

I think the following problem is a good exercise. In a List of Lists, merge lists which define neighbour intervals: for example, ...
5answers
811 views

### How to switch from array to string?

Considering we have an array: a = {2/3, 4/5, 9/7, 3/7, 1/7, 1/9}; How can I get this to be: "2/3 4/5 9/7 3/7 1/7 1/9" ...
5answers
96 views

### Build a new flat list from a mix of part items and part spans

I want to modify a list of table row by adding an extra column. For that I Map the data with a pure function that evluate the new column value from exisiting one ...
1answer
113 views

### How to joint symbolic expressions together [duplicate]

I want to joint symbolic expressions together to create a another symbolic expressions. one way to do that is as follows: ...
2answers
175 views

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2answers
71 views

### Building other matrices from these ones

First of all, I want to know if it is possible to make a constraint in a set of matrices that I have to obtain a subset. For example, if I have a set of square matrices ...
1answer
50 views

### How to use 'Join' and '& /@' : combining all .csv files in a directory into a single .csv file automatically

I would like to import all .csv files in a directory and combine them into a single file using Join. I can do this manually but when I try to automate it using <...
0answers
45 views

### How to define a symbollic matrix with variables and numbers

Newbie here. I want to define a (user-defined)function to return symmetric matrices, as I need to define quite a few tensors. I am able to do this using strings. But I need the matrix entries to be ...
1answer
76 views

### How to use Strings and Functions With Conditions

Very new to Mathematica so this might be really simple. I have the function pow[x_,r_]:= x^r where r is rational due to ...
2answers
414 views

### How to concatenate functions and strings

I have f[x_]=Log[1+x] g[x_]=TraditionalForm[Series[f[x], {x, 0, 4}]] Is there a way to get the answer to print out as ...