From 42ec7286b2d36a9ba22925f816a17cb1cc2aa5ce Mon Sep 17 00:00:00 2001 From: chai Date: Sat, 30 Oct 2021 11:32:16 +0800 Subject: + Penlight --- .../Libraries/Penlight/docs/libraries/pl.data.html | 571 +++++++++++++++++++++ 1 file changed, 571 insertions(+) create mode 100644 Data/Libraries/Penlight/docs/libraries/pl.data.html (limited to 'Data/Libraries/Penlight/docs/libraries/pl.data.html') diff --git a/Data/Libraries/Penlight/docs/libraries/pl.data.html b/Data/Libraries/Penlight/docs/libraries/pl.data.html new file mode 100644 index 0000000..736e82e --- /dev/null +++ b/Data/Libraries/Penlight/docs/libraries/pl.data.html @@ -0,0 +1,571 @@ + + + + + Penlight Documentation + + + + +
+ +
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+ +

Module pl.data

+

Reading and querying simple tabular data.

+

+ + + +

+data.read 'test.txt'
+==> {{10,20},{2,5},{40,50},fieldnames={'x','y'},delim=','}
+
+ +

Provides a way of creating basic SQL-like queries.

+ + +
+require 'pl'
+local d = data.read('xyz.txt')
+local q = d:select('x,y,z where x > 3 and z < 2 sort by y')
+for x,y,z in q do
+    print(x,y,z)
+end
+
+ +

See the Guide

+ +

Dependencies: pl.utils, pl.array2d (fallback methods)

+

+ + +

Functions

+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
Data.column_by_name (name)return a particular column as a list of values (method).
Data.select (condn)return a query iterator on this data (method).
Data.select_row (condn)return a row iterator on this data (method).
Data.copy_select (condn)return a new data object based on this query (method).
Data.column_names ()return the field names of this data object (method).
Data.write_row (f)write out a row (method).
Data.write (f)write data out to file (method).
read (file, cnfg)read a delimited file in a Lua table.
write (data, file[, fieldnames[, delim='\t']])write 2D data to a file.
new (d[, fieldnames])create a new dataset from a table of rows.
query (data, condn, context, return_row)create a query iterator from a select string.
filter (Q, infile, outfile, dont_fail)Filter input using a query.
+ +
+
+ + +

Functions

+ +
+
+ + Data.column_by_name (name) +
+
+ return a particular column as a list of values (method). + + +

Parameters:

+
    +
  • name + either name of column, or numerical index. +
    • +
+ + + + + +
+
+ + Data.select (condn) +
+
+ return a query iterator on this data (method). + + +

Parameters:

+
    +
  • condn + string + the query expression +
    • +
+ + + +

See also:

+ + + +
+
+ + Data.select_row (condn) +
+
+ return a row iterator on this data (method). + + +

Parameters:

+
    +
  • condn + string + the query expression +
    • +
+ + + + + +
+
+ + Data.copy_select (condn) +
+
+ return a new data object based on this query (method). + + +

Parameters:

+
    +
  • condn + string + the query expression +
    • +
+ + + + + +
+
+ + Data.column_names () +
+
+ return the field names of this data object (method). + + + + + + + +
+
+ + Data.write_row (f) +
+
+ write out a row (method). + + +

Parameters:

+
    +
  • f + file-like object +
    • +
+ + + + + +
+
+ + Data.write (f) +
+
+ write data out to file (method). + + +

Parameters:

+
    +
  • f + file-like object +
    • +
+ + + + + +
+
+ + read (file, cnfg) +
+
+ read a delimited file in a Lua table. + By default, attempts to treat first line as separated list of fieldnames. + + +

Parameters:

+
    +
  • file + a filename or a file-like object +
    • +
  • cnfg parsing options +
      +
    • delim + string + a string pattern to split fields +
      • +
    • fieldnames + array + (i.e. don't read from first line) +
      • +
    • no_convert + bool + (default is to try conversion on first data line) +
      • +
    • convert + tab + table of custom conversion functions with column keys +
      • +
    • numfields + int + indices of columns known to be numbers +
      • +
    • last_field_collect + bool + only split as many fields as fieldnames. +
      • +
    • thousands_dot + int + thousands separator in Excel CSV is '.' +
      • +
    • csv + bool + fields may be double-quoted and contain commas; + Also, empty fields are considered to be equivalent to zero. +
      • +
    +
+ +

Returns:

+
    +
  1. + data object, or nil
    2. +
  2. + error message. May be a file error, 'not a file-like object' + or a conversion error
    3. +
+ + + + +
+
+ + write (data, file[, fieldnames[, delim='\t']]) +
+
+ write 2D data to a file. + Does not assume that the data has actually been + generated with new or read. + + +

Parameters:

+
    +
  • data + 2D array +
    • +
  • file + filename or file-like object +
    • +
  • fieldnames + {string} + list of fields (optional) + (optional) +
    • +
  • delim + string + delimiter (default tab) + (default '\t') +
    • +
+ +

Returns:

+
    + + true or nil, error +
+ + + + +
+
+ + new (d[, fieldnames]) +
+
+ create a new dataset from a table of rows. + Can specify the fieldnames, else the table must have a field called + 'fieldnames', which is either a string of delimiter-separated names, + or a table of names.
+ If the table does not have a field called 'delim', then an attempt will be + made to guess it from the fieldnames string, defaults otherwise to tab. + + +

Parameters:

+
    +
  • d + the table. +
    • +
  • fieldnames + {string} + optional fieldnames + (optional) +
    • +
+ +

Returns:

+
    + + the table. +
+ + + + +
+
+ + query (data, condn, context, return_row) +
+
+ create a query iterator from a select string. + Select string has this format:
+ FIELDLIST [ where LUA-CONDN [ sort by FIELD] ]
+ FIELDLIST is a comma-separated list of valid fields, or '*'.

+ The condition can also be a table, with fields 'fields' (comma-sep string or + table), 'sort_by' (string) and 'where' (Lua expression string or function) + + +

Parameters:

+
    +
  • data + table produced by read +
    • +
  • condn + select string or table +
    • +
  • context + a list of tables to be searched when resolving functions +
    • +
  • return_row + if true, wrap the results in a row table +
    • +
+ +

Returns:

+
    +
  1. + an iterator over the specified fields, or nil
    2. +
  2. + an error message
    3. +
+ + + + +
+
+ + filter (Q, infile, outfile, dont_fail) +
+
+ Filter input using a query. + + +

Parameters:

+
    +
  • Q + string + a query string +
    • +
  • infile + filename or file-like object +
    • +
  • outfile + filename or file-like object +
    • +
  • dont_fail + bool + true if you want to return an error, not just fail +
    • +
+ + + + + +
+
+ + +
+
+
+generated by LDoc 1.4.6 +
+
+ + -- cgit v1.1-26-g67d0