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ColumnTypes
✖
ColumnTypes

New in 14.2[Experimental]

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gives the element types of the columns of the Tabular object tab.

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ColumnTypes[tab,tsel]

gives the element types of the columns selected by tsel.

Details

  • ColumnTypes is typically used to obtain type information either to convert the type or decide what operations can be done. For instance, you cannot do date operations on strings.
  • For a Tabular object tab with named columns, ColumnTypes[tab,…] returns a association of pairs coltype.
  • For a Tabular object tab with unnamed columns, ColumnTypes[tab,…] returns a list of types.
  • The column type selector tsel can have one of these forms:
  • tpatttype pattern
    tclassnamed class of types
  • Possible type patterns tpatt include cases like "Integer*" or "Quantity"::["Real64",_].
  • Possible type classes tclass include:
  • "Numbers"number types
    "MachineNumbers"machine-sized number types
    "Reals"real-valued types, including integers
    "MachineReals"machine-sized real-valued types, including integers
    "Integers"integer types
    "MachineIntegers"machine-sized integer types
    "FloatingPoint"numbers with floating-point representation
    "MachineFloatingPoint"machine-sized real and complex numbers
    "FloatingPointReals"real numbers with floating-point representation
    "MachineFloatingPointReals"machine-sized real numbers
    "FloatingPointComplexes"complex numbers with floating-point representation
    "Lists"each element is a list

Examples

open allclose all

Basic Examples  (3)Summary of the most common use cases

Find the types that are automatically selected for this Tabular object:

In[1]:=1
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https://wolfram.com/xid/0bdo36ezu-qcqgsq
Out[1]=1
In[2]:=2
✖
https://wolfram.com/xid/0bdo36ezu-laejtt
Out[2]=2

Find the types of the columns of reals:

In[1]:=1
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https://wolfram.com/xid/0bdo36ezu-unt8x2
Out[1]=1
In[2]:=2
✖
https://wolfram.com/xid/0bdo36ezu-ph00jl
Out[2]=2

Construct a Tabular object without keys from a numeric matrix:

In[1]:=1
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https://wolfram.com/xid/0bdo36ezu-0pqy61
Out[1]=1

Find the list of types of each column:

In[2]:=2
✖
https://wolfram.com/xid/0bdo36ezu-f7x01i
Out[2]=2

Scope  (15)Survey of the scope of standard use cases

Numeric Types  (1)

Take a collection of integers or missing values:

In[1]:=1
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https://wolfram.com/xid/0bdo36ezu-hw9zhe
In[2]:=2
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https://wolfram.com/xid/0bdo36ezu-7yw8sh
Out[2]=2

By default, integers will be interpreted using the "Integer64" type in this machine:

In[3]:=3
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https://wolfram.com/xid/0bdo36ezu-3r9hsc
Out[3]=3

Construct three columns with the same data but casting to different types of integers:

In[4]:=4
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https://wolfram.com/xid/0bdo36ezu-br4bx1
Out[4]=4

Check the stored types:

In[5]:=5
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https://wolfram.com/xid/0bdo36ezu-qlvli1
Out[5]=5

Boolean Type  (1)

Take a collection of Boolean or missing values:

In[1]:=1
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https://wolfram.com/xid/0bdo36ezu-6hwdxd
Out[1]=1

ToTabular automatically interprets the data as a column of "Boolean" type:

In[2]:=2
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https://wolfram.com/xid/0bdo36ezu-70a48b
Out[2]=2
In[3]:=3
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https://wolfram.com/xid/0bdo36ezu-cj7wu1
Out[3]=3

String Type  (1)

Take a collection of words or missing values:

In[1]:=1
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https://wolfram.com/xid/0bdo36ezu-ovrohd
Out[1]=1

ToTabular automatically interprets the data as a column of "String" type:

In[2]:=2
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https://wolfram.com/xid/0bdo36ezu-oe0pz1
Out[2]=2
In[3]:=3
✖
https://wolfram.com/xid/0bdo36ezu-k6hufl
Out[3]=3

Quantity Types  (2)

Take a collection of Quantity durations and missing values:

In[1]:=1
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https://wolfram.com/xid/0bdo36ezu-7h9sz4
Out[1]=1
In[2]:=2
✖
https://wolfram.com/xid/0bdo36ezu-h9hya8
Out[2]=2

The values are stored using "Real64" magnitudes and a common unit of "Seconds":

In[3]:=3
✖
https://wolfram.com/xid/0bdo36ezu-mx105s
Out[3]=3

For small enough Tabular objects, the original input data is cached by default and Normal recovers it:

In[4]:=4
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https://wolfram.com/xid/0bdo36ezu-31aw6b
Out[4]=4

Specify the magnitude type and unit to use:

In[5]:=5
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https://wolfram.com/xid/0bdo36ezu-qu9qe4
Out[5]=5
In[6]:=6
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https://wolfram.com/xid/0bdo36ezu-y2wqrm
Out[6]=6

The original input was not cached:

In[7]:=7
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https://wolfram.com/xid/0bdo36ezu-yerj87
Out[7]=7

Quantities of different dimensions can be stored using the "InertExpression" type:

In[1]:=1
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https://wolfram.com/xid/0bdo36ezu-kf3pyn
Out[1]=1
In[2]:=2
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https://wolfram.com/xid/0bdo36ezu-dh84ci
Out[2]=2
In[3]:=3
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https://wolfram.com/xid/0bdo36ezu-buf5yi
Out[3]=3

Trying to impose a specific "Quantity" type will result in missing values:

In[4]:=4
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https://wolfram.com/xid/0bdo36ezu-mgefwg
Out[4]=4
In[5]:=5
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https://wolfram.com/xid/0bdo36ezu-6f461s
Out[5]=5

Date & Time Types  (3)

Take a collection of dates:

In[1]:=1
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https://wolfram.com/xid/0bdo36ezu-0nzv32
Out[1]=1

Create a Tabular object with automatic type detection:

In[2]:=2
✖
https://wolfram.com/xid/0bdo36ezu-nwc9x2
Out[2]=2
In[3]:=3
✖
https://wolfram.com/xid/0bdo36ezu-lh1th4
Out[3]=3

Specify a type to convert to granularity "Day" when dates are extracted:

In[4]:=4
✖
https://wolfram.com/xid/0bdo36ezu-m10mw9
Out[4]=4
In[5]:=5
✖
https://wolfram.com/xid/0bdo36ezu-ykdqbp
Out[5]=5
In[6]:=6
✖
https://wolfram.com/xid/0bdo36ezu-gfd1gu
Out[6]=6

Take a collection of times:

In[1]:=1
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https://wolfram.com/xid/0bdo36ezu-eez1x4
Out[1]=1

Create a Tabular object with automatic type detection:

In[2]:=2
✖
https://wolfram.com/xid/0bdo36ezu-i2qqbn
Out[2]=2
In[3]:=3
✖
https://wolfram.com/xid/0bdo36ezu-eq3w5h
Out[3]=3

Specify a type to convert to granularity "Hour" when times are extracted:

In[4]:=4
✖
https://wolfram.com/xid/0bdo36ezu-16epjm
Out[4]=4
In[5]:=5
✖
https://wolfram.com/xid/0bdo36ezu-fxdnwi
Out[5]=5
In[6]:=6
✖
https://wolfram.com/xid/0bdo36ezu-4pf164
Out[6]=6

Specify dates with a different calendar:

In[1]:=1
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https://wolfram.com/xid/0bdo36ezu-rarm7g
Out[1]=1
In[2]:=2
✖
https://wolfram.com/xid/0bdo36ezu-2r057v
Out[2]=2
In[3]:=3
✖
https://wolfram.com/xid/0bdo36ezu-yqg4zy
Out[3]=3
In[4]:=4
✖
https://wolfram.com/xid/0bdo36ezu-n88pyv
Out[4]=4

Categorical Type  (2)

Take a collection of strings:

In[1]:=1
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https://wolfram.com/xid/0bdo36ezu-4lpghr
Out[1]=1

ToTabular automatically interprets the data as a column of "String" type:

In[2]:=2
✖
https://wolfram.com/xid/0bdo36ezu-blahrj
Out[2]=2
In[3]:=3
✖
https://wolfram.com/xid/0bdo36ezu-3m8bl2
Out[3]=3

Explicitly specify a "Categorical" type for the column, categorizing the data:

In[4]:=4
✖
https://wolfram.com/xid/0bdo36ezu-vb77n1
Out[4]=4
In[5]:=5
✖
https://wolfram.com/xid/0bdo36ezu-t5er0h
Out[5]=5

Extract the categories:

In[6]:=6
✖
https://wolfram.com/xid/0bdo36ezu-5p34kc
Out[6]=6
In[7]:=7
✖
https://wolfram.com/xid/0bdo36ezu-0qm41m
Out[7]=7

Split a gene sequence into a list of the nucleotide bases:

In[1]:=1
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https://wolfram.com/xid/0bdo36ezu-izhm10

Create a Tabular object with specific categories of the nucleotide bases:

In[2]:=2
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https://wolfram.com/xid/0bdo36ezu-9gmrb4
Out[2]=2
In[3]:=3
✖
https://wolfram.com/xid/0bdo36ezu-71igk2
Out[3]=3
In[4]:=4
✖
https://wolfram.com/xid/0bdo36ezu-hpjqjs
Out[4]=4

Visualize the beginning of the sequence:

In[5]:=5
✖
https://wolfram.com/xid/0bdo36ezu-x9i6c4
Out[5]=5

Categorical Ordered Type  (1)

Take a collection of sizes:

In[1]:=1
✖
https://wolfram.com/xid/0bdo36ezu-8day37
Out[1]=1
In[2]:=2
✖
https://wolfram.com/xid/0bdo36ezu-c4azhl
Out[2]=2

Create a Tabular object with automatic type detection:

In[3]:=3
✖
https://wolfram.com/xid/0bdo36ezu-nbs0gj
Out[3]=3

The automatically detected type is "String":

In[4]:=4
✖
https://wolfram.com/xid/0bdo36ezu-rpl2xn
Out[4]=4

Specify the "CategoricalOrdered" type providing the list categories, which defines the ordering:

In[5]:=5
✖
https://wolfram.com/xid/0bdo36ezu-op4yc2
Out[5]=5
In[6]:=6
✖
https://wolfram.com/xid/0bdo36ezu-q6gw9e
Out[6]=6

Lists & Tuples  (2)

Take a collection of integer tuples:

In[1]:=1
✖
https://wolfram.com/xid/0bdo36ezu-l998e0
Out[1]=1
In[2]:=2
✖
https://wolfram.com/xid/0bdo36ezu-g8p5iw
Out[2]=2
In[3]:=3
✖
https://wolfram.com/xid/0bdo36ezu-dlbw1q
Out[3]=3

Specify the type of the elements of the tuples:

In[4]:=4
✖
https://wolfram.com/xid/0bdo36ezu-go9t6e
Out[4]=4
In[5]:=5
✖
https://wolfram.com/xid/0bdo36ezu-1rat4z
Out[5]=5

Take a collection of tuples of objects of various types:

In[1]:=1
✖
https://wolfram.com/xid/0bdo36ezu-80r5oq
Out[1]=1

Create a Tabular object with automatic type detection:

In[2]:=2
✖
https://wolfram.com/xid/0bdo36ezu-p81eiy
Out[2]=2
In[3]:=3
✖
https://wolfram.com/xid/0bdo36ezu-nattje
Out[3]=3

Specify the types of the elements of the tuples:

In[4]:=4
✖
https://wolfram.com/xid/0bdo36ezu-2hoabh
Out[4]=4
In[5]:=5
✖
https://wolfram.com/xid/0bdo36ezu-v56inb
Out[5]=5

General Expressions  (1)

Take a collection of regions:

In[1]:=1
✖
https://wolfram.com/xid/0bdo36ezu-zhlu5c
Out[1]=1

Creating a Tabular object assigns type "Expression" to general Wolfram Language expressions:

In[2]:=2
✖
https://wolfram.com/xid/0bdo36ezu-1d9fpm
Out[2]=2
In[3]:=3
✖
https://wolfram.com/xid/0bdo36ezu-5lrdn7
Out[3]=3

Column Selectors  (1)

Get column types for all columns:

In[1]:=1
✖
https://wolfram.com/xid/0bdo36ezu-vectp8
Out[1]=1
In[2]:=2
✖
https://wolfram.com/xid/0bdo36ezu-7u8v6l
Out[2]=2

Extract column types for two columns:

In[3]:=3
✖
https://wolfram.com/xid/0bdo36ezu-iiiea
Out[3]=3

Extract columns of Boolean type:

In[4]:=4
✖
https://wolfram.com/xid/0bdo36ezu-tb7tuu
Out[4]=4

Extract columns of any integer type:

In[5]:=5
✖
https://wolfram.com/xid/0bdo36ezu-gjqj8w
Out[5]=5

Extract columns that are either string or Boolean:

In[6]:=6
✖
https://wolfram.com/xid/0bdo36ezu-vlodef
Out[6]=6

Applications  (1)Sample problems that can be solved with this function

Create a TabularRow with automatic input type detection:

In[1]:=1
✖
https://wolfram.com/xid/0bdo36ezu-wzwqpg
Out[1]=1

Column types:

In[2]:=2
✖
https://wolfram.com/xid/0bdo36ezu-lj4as5
Out[2]=2

Specify types:

In[3]:=3
✖
https://wolfram.com/xid/0bdo36ezu-4bsag3
Out[3]=3

Column types:

In[4]:=4
✖
https://wolfram.com/xid/0bdo36ezu-evfvhg
Out[4]=4
Wolfram Research (2025), ColumnTypes, Wolfram Language function, https://reference.wolfram.com/language/ref/ColumnTypes.html.
✖
Wolfram Research (2025), ColumnTypes, Wolfram Language function, https://reference.wolfram.com/language/ref/ColumnTypes.html.

Text

Wolfram Research (2025), ColumnTypes, Wolfram Language function, https://reference.wolfram.com/language/ref/ColumnTypes.html.

✖
Wolfram Research (2025), ColumnTypes, Wolfram Language function, https://reference.wolfram.com/language/ref/ColumnTypes.html.

CMS

Wolfram Language. 2025. "ColumnTypes." Wolfram Language & System Documentation Center. Wolfram Research. https://reference.wolfram.com/language/ref/ColumnTypes.html.

✖
Wolfram Language. 2025. "ColumnTypes." Wolfram Language & System Documentation Center. Wolfram Research. https://reference.wolfram.com/language/ref/ColumnTypes.html.

APA

Wolfram Language. (2025). ColumnTypes. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/ColumnTypes.html

✖
Wolfram Language. (2025). ColumnTypes. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/ColumnTypes.html

BibTeX

@misc{reference.wolfram_2025_columntypes, author="Wolfram Research", title="{ColumnTypes}", year="2025", howpublished="\url{https://reference.wolfram.com/language/ref/ColumnTypes.html}", note=[Accessed: 15-May-2025 ]}

✖
@misc{reference.wolfram_2025_columntypes, author="Wolfram Research", title="{ColumnTypes}", year="2025", howpublished="\url{https://reference.wolfram.com/language/ref/ColumnTypes.html}", note=[Accessed: 15-May-2025 ]}

BibLaTeX

@online{reference.wolfram_2025_columntypes, organization={Wolfram Research}, title={ColumnTypes}, year={2025}, url={https://reference.wolfram.com/language/ref/ColumnTypes.html}, note=[Accessed: 15-May-2025 ]}

✖
@online{reference.wolfram_2025_columntypes, organization={Wolfram Research}, title={ColumnTypes}, year={2025}, url={https://reference.wolfram.com/language/ref/ColumnTypes.html}, note=[Accessed: 15-May-2025 ]}