CSV Tools

Some tools for working with and analysing CSV files, including:

• csvproject: project columns from a CSV file
• csvreport: output a report for each column showing the type of data, number of empty values, and so on.

Usage

Here’s an example input file:

# test.csv:
make,model,derivative
ford,capri,2.0L
ford,capri,3.0L
citroen,ds,2.3L

csvproject

Project as in projection. Select and output columns from the input file.

$ csvproject test.csv -c make
ford
ford
citroen

$ csvproject test.csv -c make -c derivative
ford,2.0L
ford,3.0L
citroen,2.3L

$ # exclude columns instead of including:
$ csvproject test.csv -e model
ford,2.0L
ford,3.0L
citroen,2.3L

$ csvproject test.csv -c model --headers-out
model
capri
capri
ds

$ csvproject test.csv -c 1 --no-headers
model
capri
capri
ds

$ # here's an example using stdin:
$ csvproject -c make < test.csv
ford
ford
citroen

$ # use a tab delimiter:
$ csvproject -d$'\t' < test.tsv
ford,capri,2.0L
ford,capri,3.0L
citroen,ds,2.3L

csvreport

Generate a report showing the range and type of values for each column selected

$ csvreport test.csv -c make
Column: make
┌────────────────────┬────────────────────────────────────────────────────────────┐
│ Type               │ String                                                     │
├────────────────────┼────────────────────────────────────────────────────────────┤
│ count              │ 3                                                          │
├────────────────────┼────────────────────────────────────────────────────────────┤
│ min                │ citroen                                                    │
├────────────────────┼────────────────────────────────────────────────────────────┤
│ max                │ ford                                                       │
├────────────────────┼────────────────────────────────────────────────────────────┤
│ minLength          │ 4                                                          │
├────────────────────┼────────────────────────────────────────────────────────────┤
│ maxLength          │ 7                                                          │
├────────────────────┼────────────────────────────────────────────────────────────┤
│ Unique strings (2) │ ford, citroen                                              │
├────────────────────┼────────────────────────────────────────────────────────────┤
│ emptyCount         │ 0                                                          │
└────────────────────┴────────────────────────────────────────────────────────────┘

TODO

• [x] Write usage docs.
• [x] Support files without a header row.
• [x] Support input from stdin.
• [x] Write some tests.
• [x] Add flag to exclude columns instead of including.
• [ ] Improve test coverage.
• [ ] Support passing options from a config file.