# Combine(Merge) Columns
**URL:** https://discourse.julialang.org/t/combine-merge-columns/56202
**Category:** New to Julia
**Tags:** dataframes
**Created:** [February 28, 2021, 6:02pm UTC](https://discourse.julialang.org/t/combine-merge-columns/56202 "2021-02-28T18:02:50Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@dbjulia](https://discourse.julialang.org/u/dbjulia)
#### Post date: [February 28, 2021, 6:02pm UTC](https://discourse.julialang.org/t/combine-merge-columns/56202/1 "2021-02-28T18:02:50Z")
Programming & Julia newbie here: I have googled and searched the documentation and tried various ways to do this but I cannot come up with a solution and it seems so simple. Is there a way to combine two columns within a dataframe. See the below example, how could I make a column that would be named “C” and contain A:1 as it first row? The use case for me would be creating an ID column in an datafame that doesn’t contain one. I know there is a issue with A being a string and B being a Int is there a way to overcome that? Thanks in advance.
using DataFrames
df = DataFrame()
df.A = [“A”,“B”,“C”,“D”]
df.B = 1:4
display(df)
4×2 DataFrame
Row │ A B
│ String Int64
─────┼───────────────
1 │ A 1
2 │ B 2
3 │ C 3
4 │ D 4
---
### Author:  [@pdeffebach](https://discourse.julialang.org/u/pdeffebach)
#### Post date: [February 28, 2021, 6:07pm UTC](https://discourse.julialang.org/t/combine-merge-columns/56202/2 "2021-02-28T18:07:06Z")
Easiest solution:
```julia
df.C = string.(df.A, ":", df.B)
```
`transform` solution
```julia
transform!(df, [:A, :B] => ByRow((A, B) -> string(A, ":", B)) => :C)
```
DataFramesMeta solution:
```julia
@transform(df, C = string.(:A, ":", :B))
```
---
### Author:  [@dbjulia](https://discourse.julialang.org/u/dbjulia)
#### Post date: [February 28, 2021, 7:16pm UTC](https://discourse.julialang.org/t/combine-merge-columns/56202/3 "2021-02-28T19:16:18Z")
Thanks, pdeffebach that worked, appreciate the quick and thorough response.