nushell/docs/commands/from-csv.md

3.8 KiB

from csv

Converts csv data into table. Use this when nushell cannot determine the input file extension.

Example

Let's say we have the following file:

> cat pets.txt
animal, name, age
cat, Tom, 7
dog, Alfred, 10
chameleon, Linda, 1

pets.txt is actually a .csv file but it has the .txt extension, open is not able to convert it into a table:

> open pets.txt
animal, name, age
cat, Tom, 7
dog, Alfred, 10
chameleon, Linda, 1

To get a table from pets.txt we need to use the from csv command:

> open pets.txt | from csv
━━━┯━━━━━━━━━━━┯━━━━━━━━━┯━━━━━━
 # │ animal    │  name   │  age
───┼───────────┼─────────┼──────
 0 │ cat       │  Tom    │  7
 1 │ dog       │  Alfred │  10
 2 │ chameleon │  Linda  │  1
━━━┷━━━━━━━━━━━┷━━━━━━━━━┷━━━━━━

To ignore the csv headers use --headerless:

━━━┯━━━━━━━━━━━┯━━━━━━━━━┯━━━━━━━━━
 # │ Column1   │ Column2 │ Column3
───┼───────────┼─────────┼─────────
 0 │ dog       │  Alfred │  10
 1 │ chameleon │  Linda  │  1
━━━┷━━━━━━━━━━━┷━━━━━━━━━┷━━━━━━━━━

To split on a character other than ',' use --separator:

> open pets.txt
animal; name; age
cat; Tom; 7
dog; Alfred; 10
chameleon; Linda; 1
> open pets.txt | from csv --separator ';'
━━━┯━━━━━━━━━━━┯━━━━━━━━━┯━━━━━━
 # │ animal    │  name   │  age
───┼───────────┼─────────┼──────
 0 │ cat       │  Tom    │  7
 1 │ dog       │  Alfred │  10
 2 │ chameleon │  Linda  │  1
━━━┷━━━━━━━━━━━┷━━━━━━━━━┷━━━━━━

To use this command to open a csv with separators other than a comma, use the --raw switch of open to open the csv, otherwise the csv will enter from csv as a table split on commas rather than raw text.

> mv pets.txt pets.csv
> open pets.csv | from csv --separator ';'
error: Expected a string from pipeline
- shell:1:16
1 | open pets.csv | from csv --separator ';'
  |                 ^^^^^^^^ requires string input
- shell:1:0
1 | open pets.csv | from csv --separator ';'
  |  value originates from here

> open pets.csv --raw | from csv --separator ';'
━━━┯━━━━━━━━━━━┯━━━━━━━━━┯━━━━━━
 # │ animal    │  name   │  age
───┼───────────┼─────────┼──────
 0 │ cat       │  Tom    │  7
 1 │ dog       │  Alfred │  10
 2 │ chameleon │  Linda  │  1
━━━┷━━━━━━━━━━━┷━━━━━━━━━┷━━━━━━

The string '\t' can be used to separate on tabs. Note that this is the same as using the from tsv command.

Newlines '\n' are not acceptable separators.

Note that separators are currently provided as strings and need to be wrapped in quotes.

> open pets.csv --raw | from csv --separator ;
- shell:1:43
1 | open pets.csv --raw | from csv --separator ;
  |                                            ^

It is also considered an error to use a separator greater than one char:

> open pets.txt | from csv --separator '123'
error: Expected a single separator char from --separator
- shell:1:37
1 | open pets.txt | from csv --separator '123'
  |                                      ^^^^^ requires a single character string input