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Put
✖
Put

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expr>>filename

writes expr to a file.

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Put[expr1,expr2,…,"filename"]

writes a sequence of expressions expri to a file.

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Put["filename"]

creates an empty file with the specified name.

Details and Options

  • Put starts writing output at the beginning of the file. It deletes whatever was previously in the file.
  • Put inserts a newline (line feed) at the end of its output.
  • expr>>filename is equivalent to expr>>"filename". The double quotes can be omitted if the file name is of the form specified in "Operator Input Forms".
  • It is conventional to use names that end with .wl or .m for files containing Wolfram Language input.
  • Put[…,OutputStream[…]] will append to the given stream.
  • Put works with cloud and local objects.
  • Put by default writes expressions in InputForm.
  • Put[OutputForm[expr],"filename"] generates OutputForm.
  • Put by default uses the character encoding "PrintableASCII" when creating a file. Add the option CharacterEncodingenc to specify a different encoding.
  • When writing to an open file or an OutputStream object, the current encoding of the output stream will be used by default. Add the option CharacterEncodingenc to temporarily change the encoding of the stream for the duration of Put.
  • Put[…,File["file"]] is also supported.

Examples

open allclose all

Basic Examples  (1)Summary of the most common use cases

Compute a value to store in a temporary file:

In[1]:=1
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https://wolfram.com/xid/0dejik-bvupiv
Out[1]=1

Set the current directory to one for temporary files:

In[2]:=2
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https://wolfram.com/xid/0dejik-bqgnsu

Put the value of a into a file:

In[3]:=3
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https://wolfram.com/xid/0dejik-czju2s

The file now contains the value:

In[4]:=4
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https://wolfram.com/xid/0dejik-gqbkkz

Reset the directory:

In[5]:=5
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https://wolfram.com/xid/0dejik-b9j8zj

Scope  (4)Survey of the scope of standard use cases

Local objects can be used with Put and Get to store expressions persistently:

In[1]:=1
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https://wolfram.com/xid/0dejik-3g94j
Out[1]=1
In[2]:=2
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https://wolfram.com/xid/0dejik-djmveh
Out[2]=2

Cloud objects can be used with Put and Get to store expressions in the cloud:

In[1]:=1
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https://wolfram.com/xid/0dejik-vqh2on
Out[1]=1
In[2]:=2
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https://wolfram.com/xid/0dejik-rvo75y
Out[2]=2

Put expression in the file specified by the File object:

In[1]:=1
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https://wolfram.com/xid/0dejik-juag3f
Out[1]=1
In[2]:=2
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https://wolfram.com/xid/0dejik-xqumqa
In[3]:=3
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https://wolfram.com/xid/0dejik-e46ohk

Create a file and open it for writing:

In[1]:=1
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https://wolfram.com/xid/0dejik-tnb5jj
Out[1]=1

Put an expression to the stream:

In[2]:=2
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https://wolfram.com/xid/0dejik-n3jwts

Close the stream:

In[3]:=3
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https://wolfram.com/xid/0dejik-0bc5fz
Out[3]=3

The file contents were written using the CharacterEncoding option of the stream:

In[4]:=4
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https://wolfram.com/xid/0dejik-xuoion

Options  (1)Common values & functionality for each option

CharacterEncoding  (1)

By default, the encoding "PrintableASCII" is used when writing to files:

In[1]:=1
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https://wolfram.com/xid/0dejik-6qhu2b

Special characters are written out as long names, which ensures they can be read on any system:

In[2]:=2
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https://wolfram.com/xid/0dejik-fle0ve
Out[2]=2

Specify the common encoding "UTF-8":

In[3]:=3
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https://wolfram.com/xid/0dejik-uacv0l

Special characters are written directly in the encoding, saving space at the cost of portability:

In[4]:=4
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https://wolfram.com/xid/0dejik-7g2b46
Out[4]=4

Properties & Relations  (2)Properties of the function, and connections to other functions

Put overwrites any existing file contents:

In[1]:=1
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https://wolfram.com/xid/0dejik-dq2hgm
In[2]:=2
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https://wolfram.com/xid/0dejik-jb077o

Only the second expression is in the file:

In[4]:=4
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https://wolfram.com/xid/0dejik-c8kv6v

Use PutAppend to add to an existing file:

In[5]:=5
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https://wolfram.com/xid/0dejik-dp87h7
In[6]:=6
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https://wolfram.com/xid/0dejik-i7i7wo

When writing to a stream, Put behaves essentially like PutAppend:

In[1]:=1
✖
https://wolfram.com/xid/0dejik-hb4qum
Out[1]=1
In[2]:=2
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https://wolfram.com/xid/0dejik-tamr01

Close the stream:

In[3]:=3
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https://wolfram.com/xid/0dejik-qwru9r
Out[3]=3

The file has all three expressions, not just the last one:

In[4]:=4
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https://wolfram.com/xid/0dejik-hcuh00

Possible Issues  (1)Common pitfalls and unexpected behavior

The form expr>>filename treats filename as a literal name, not an expression to be evaluated:

In[1]:=1
✖
https://wolfram.com/xid/0dejik-pf1qwg
Out[1]=1
In[2]:=2
✖
https://wolfram.com/xid/0dejik-8w0cxz

The file that was written is called "file", not the name contained in the variable file:

In[4]:=4
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https://wolfram.com/xid/0dejik-cpitp3
Out[4]=4
In[5]:=5
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https://wolfram.com/xid/0dejik-safzw7
Out[5]=5

Use the form Put[expr,filename] to write to the file whose name is stored in file:

In[6]:=6
✖
https://wolfram.com/xid/0dejik-nw0sth
Out[7]=7
Wolfram Research (1988), Put, Wolfram Language function, https://reference.wolfram.com/language/ref/Put.html (updated 2016).
✖
Wolfram Research (1988), Put, Wolfram Language function, https://reference.wolfram.com/language/ref/Put.html (updated 2016).

Text

Wolfram Research (1988), Put, Wolfram Language function, https://reference.wolfram.com/language/ref/Put.html (updated 2016).

✖
Wolfram Research (1988), Put, Wolfram Language function, https://reference.wolfram.com/language/ref/Put.html (updated 2016).

CMS

Wolfram Language. 1988. "Put." Wolfram Language & System Documentation Center. Wolfram Research. Last Modified 2016. https://reference.wolfram.com/language/ref/Put.html.

✖
Wolfram Language. 1988. "Put." Wolfram Language & System Documentation Center. Wolfram Research. Last Modified 2016. https://reference.wolfram.com/language/ref/Put.html.

APA

Wolfram Language. (1988). Put. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/Put.html

✖
Wolfram Language. (1988). Put. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/Put.html

BibTeX

@misc{reference.wolfram_2025_put, author="Wolfram Research", title="{Put}", year="2016", howpublished="\url{https://reference.wolfram.com/language/ref/Put.html}", note=[Accessed: 20-June-2025 ]}

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@misc{reference.wolfram_2025_put, author="Wolfram Research", title="{Put}", year="2016", howpublished="\url{https://reference.wolfram.com/language/ref/Put.html}", note=[Accessed: 20-June-2025 ]}

BibLaTeX

@online{reference.wolfram_2025_put, organization={Wolfram Research}, title={Put}, year={2016}, url={https://reference.wolfram.com/language/ref/Put.html}, note=[Accessed: 20-June-2025 ]}

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@online{reference.wolfram_2025_put, organization={Wolfram Research}, title={Put}, year={2016}, url={https://reference.wolfram.com/language/ref/Put.html}, note=[Accessed: 20-June-2025 ]}