# How to dynamically call a column in a @where macro?

**URL:** <https://discourse.julialang.org/t/how-to-dynamically-call-a-column-in-a-where-macro/5503>\
**Category:** Data\
**Tags:** question\
**Created:** [August 22, 2017, 1:03pm UTC](https://discourse.julialang.org/t/how-to-dynamically-call-a-column-in-a-where-macro/5503 "2017-08-22T13:03:50Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![sylvaticus](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/sylvaticus/32/203883_2.png) [@sylvaticus](https://discourse.julialang.org/u/sylvaticus)\
**Post date:** [August 22, 2017, 1:03pm UTC](https://discourse.julialang.org/t/how-to-dynamically-call-a-column-in-a-where-macro/5503/1 "2017-08-22T13:03:50Z")

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How can I dynamically refer to a column name (i.e., a Symbol) within a `@where` macro ?

```julia
using DataFrames, DataFramesMeta
df = DataFrame(x=Int64[1,2,3,4,5])
name = "x"
nameS = Symbol(name)
df2 = @where(df, :x .>= 2) # ok
df2 = @where(df, nameS .>= 2) # MethodError

```

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**Author:** ![tshort](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/tshort/32/43_2.png) [@tshort](https://discourse.julialang.org/u/tshort)\
**Post date:** [August 22, 2017, 3:30pm UTC](https://discourse.julialang.org/t/how-to-dynamically-call-a-column-in-a-where-macro/5503/2 "2017-08-22T15:30:55Z")

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I think you want the following, but I’m not where I can check it:

```julia
df2 = @where(df, _I_(nameS) .>= 2)

```

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<div class="post-metadata">

**Author:** ![sylvaticus](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/sylvaticus/32/203883_2.png) [@sylvaticus](https://discourse.julialang.org/u/sylvaticus)\
**Post date:** [August 23, 2017, 12:27pm UTC](https://discourse.julialang.org/t/how-to-dynamically-call-a-column-in-a-where-macro/5503/3 "2017-08-23T12:27:20Z")

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Thank you, that’s work.  
For reference, `_I_` is documented in the `@with` section of [DataFrameMeta.jl README](https://github.com/JuliaStats/DataFramesMeta.jl).