tstoolbox.tstoolbox.convert_index

tstoolbox.tstoolbox.convert_index(to, interval=None, epoch='julian', input_ts='-', columns=None, start_date=None, end_date=None, round_index=None, dropna='no', clean=False, names=None, source_units=None, target_units=None, skiprows=None)

Convert datetime to/from Julian dates from different epochs.

Parameters:

• to (str) – One of ‘number’ or ‘datetime’. If ‘number’, the source time-series should have a datetime index to convert to a number. If ‘datetime’, source data should be a number and the converted index will be datetime.

• interval –

  [optional, defaults to None, transformation]

  The interval parameter defines the unit time. One of the pandas offset codes. The default of ‘None’ will set the unit time for all defined epochs to daily except ‘unix’ which will default to seconds.

  You can give any smaller unit time than daily for all defined epochs except ‘unix’ which requires an interval less than seconds. For an epoch that begins with an arbitrary date, you can use any interval equal to or smaller than the frequency of the time-series.

  Alias	Description
  N	Nanoseconds
  U	microseconds
  L	milliseconds
  S	Secondly
  T	Minutely
  H	Hourly
  D	calendar Day
  W	Weekly
  M	Month end
  MS	Month Start
  Q	Quarter end
  QS	Quarter Start
  A	Annual end
  AS	Annual Start

  Business offset codes.

  Alias	Description
  B	Business day
  BM	Business Month end
  BMS	Business Month Start
  BQ	Business Quarter end
  BQS	Business Quarter Start
  BA	Business Annual end
  BAS	Business Annual Start
  C	Custom business day (experimental)
  CBM	Custom Business Month end
  CBMS	Custom Business Month Start

  Weekly has the following anchored frequencies:

  Alias	Equivalents	Description
  W-SUN	W	Weekly frequency (SUNdays)
  W-MON		Weekly frequency (MONdays)
  W-TUE		Weekly frequency (TUEsdays)
  W-WED		Weekly frequency (WEDnesdays)
  W-THU		Weekly frequency (THUrsdays)
  W-FRI		Weekly frequency (FRIdays)
  W-SAT		Weekly frequency (SATurdays)

  Quarterly frequencies (Q, BQ, QS, BQS) and annual frequencies (A, BA, AS, BAS) replace the “x” in the “Alias” column to have the following anchoring suffixes:

  Alias	Examples	Equivalents	Description
  x-DEC	A-DEC Q-DEC AS-DEC QS-DEC	A Q AS QS	year ends end of DECember
  x-JAN			year ends end of JANuary
  x-FEB			year ends end of FEBruary
  x-MAR			year ends end of MARch
  x-APR			year ends end of APRil
  x-MAY			year ends end of MAY
  x-JUN			year ends end of JUNe
  x-JUL			year ends end of JULy
  x-AUG			year ends end of AUGust
  x-SEP			year ends end of SEPtember
  x-OCT			year ends end of OCTober
  x-NOV			year ends end of NOVember

epochstr

[optional, defaults to ‘julian’, transformation]

Can be one of, ‘julian’, ‘reduced’, ‘modified’, ‘truncated’, ‘dublin’, ‘cnes’, ‘ccsds’, ‘lop’, ‘lilian’, ‘rata_die’, ‘mars_sol_date’, ‘unix’, or a date and time.

If supplying a date and time, most formats are recognized, however the closer the format is to ISO 8601 the better. Also should check and make sure date was parsed as expected. If supplying only a date, the epoch starts at midnight the morning of that date.

The ‘unix’ epoch uses a default interval of seconds, and all other defined epochs use a default interval of ‘daily’.

epoch	Epoch	Calculation	Notes
julian	4713-01-01:12 BCE	JD
reduced	1858-11-16:12	JD - 2400000	[ [1] ] [ [2] ]
modified	1858-11-17:00	JD - 2400000.5	SAO 1957
truncated	1968-05-24:00	floor (JD - 2440000.5)	NASA 1979, integer
dublin	1899-12-31:12	JD - 2415020	IAU 1955
cnes	1950-01-01:00	JD - 2433282.5	CNES [ [3] ]
ccsds	1958-01-01:00	JD - 2436204.5	CCSDS [ [3] ]
lop	1992-01-01:00	JD - 2448622.5	LOP [ [3] ]
lilian	1582-10-15[13]	floor (JD - 2299159.5)	Count of days of the Gregorian calendar, integer
rata_die	0001-01-01[13] proleptic Gregorian calendar	floor (JD - 1721424.5)	Count of days of the Common Era, integer
mars_sol	1873-12-29:12	(JD - 2405522) /1.02749	Count of Martian days
unix	1970-01-01 T00:00:00	JD - 2440587.5	seconds

[1]

. Hopkins, Jeffrey L. (2013). Using Commercial Amateur Astronomical Spectrographs, p. 257, Springer Science & Business Media, ISBN 9783319014425

[2]

. Palle, Pere L., Esteban, Cesar. (2014). Asteroseismology, p. 185, Cambridge University Press, ISBN 9781107470620

[3] (1,2,3)

. Theveny, Pierre-Michel. (10 September 2001). “Date Format” The TPtime Handbook. Media Lab.

input_tsstr

[optional though required if using within Python, default is ‘-’ (stdin)]

Whether from a file or standard input, data requires a single line header of column names. The default header is the first line of the input, but this can be changed for CSV files using the ‘skiprows’ option.

Most common date formats can be used, but the closer to ISO 8601 date/time standard the better.

Comma-separated values (CSV) files or tab-separated values (TSV):

File separators will be automatically detected.

Columns can be selected by name or index, where the index for
data columns starts at 1.

Command line examples:

Keyword Example	Description
–input_ts=fn.csv	read all columns from ‘fn.csv’
–input_ts=fn.csv,2,1	read data columns 2 and 1 from ‘fn.csv’
–input_ts=fn.csv,2,skiprows=2	read data column 2 from ‘fn.csv’, skipping first 2 rows so header is read from third row
–input_ts=fn.xlsx,2,Sheet21	read all data from 2nd sheet all data from “Sheet21” of ‘fn.xlsx’
–input_ts=fn.hdf5,Table12,T2	read all data from table “Table12” then all data from table “T2” of ‘fn.hdf5’
–input_ts=fn.wdm,210,110	read DSNs 210, then 110 from ‘fn.wdm’
–input_ts=’-’	read all columns from standard input (stdin)
–input_ts=’-’ –columns=4,1	read column 4 and 1 from standard input (stdin)

If working with CSV or TSV files you can use redirection rather than use –input_ts=fname.csv. The following are identical:

From a file:

command subcmd –input_ts=fname.csv

From standard input (since ‘–input_ts=-’ is the default:

command subcmd < fname.csv

Can also combine commands by piping:

command subcmd < filein.csv | command subcmd1 > fileout.csv

Python library examples:

You must use the `input_ts=...` option where `input_ts` can be
one of a [pandas DataFrame, pandas Series, dict, tuple, list,
StringIO, or file name].

columns

[optional, defaults to all columns, input filter]

Columns to select out of input. Can use column names from the first line header or column numbers. If using numbers, column number 1 is the first data column. To pick multiple columns; separate by commas with no spaces. As used in toolbox_utils pick command.

This solves a big problem so that you don’t have to create a data set with a certain column order, you can rearrange columns when data is read in.

start_datestr

[optional, defaults to first date in time-series, input filter]

The start_date of the series in ISOdatetime format, or ‘None’ for beginning.

end_datestr

[optional, defaults to last date in time-series, input filter]

The end_date of the series in ISOdatetime format, or ‘None’ for end.

round_index

[optional, default is None which will do nothing to the index, output format]

Round the index to the nearest time point. Can significantly improve the performance since can cut down on memory and processing requirements, however be cautious about rounding to a very course interval from a small one. This could lead to duplicate values in the index.

dropnastr

[optional, defauls it ‘no’, input filter]

Set dropna to ‘any’ to have records dropped that have NA value in any column, or ‘all’ to have records dropped that have NA in all columns. Set to ‘no’ to not drop any records. The default is ‘no’.

clean

[optional, default is False, input filter]

The ‘clean’ command will repair a input index, removing duplicate index values and sorting.

skiprows: list-like or integer or callable

[optional, default is None which will infer header from first line, input filter]

Line numbers to skip (0-indexed) if a list or number of lines to skip at the start of the file if an integer.

If used in Python can be a callable, the callable function will be evaluated against the row indices, returning True if the row should be skipped and False otherwise. An example of a valid callable argument would be

lambda x: x in [0, 2].

names: str

[optional, default is None, transformation]

If None, the column names are taken from the first row after ‘skiprows’ from the input dataset.

MUST include a name for all columns in the input dataset, including the index column.

source_units: str

[optional, default is None, transformation]

If unit is specified for the column as the second field of a ‘:’ delimited column name, then the specified units and the ‘source_units’ must match exactly.

Any unit string compatible with the ‘pint’ library can be used.

target_units: str

[optional, default is None, transformation]

The purpose of this option is to specify target units for unit conversion. The source units are specified in the header line of the input or using the ‘source_units’ keyword.

The units of the input time-series or values are specified as the second field of a ‘:’ delimited name in the header line of the input or in the ‘source_units’ keyword.

Any unit string compatible with the ‘pint’ library can be used.

This option will also add the ‘target_units’ string to the column names.

tablefmtstr

[optional, default is ‘csv’, output format]

The table format. Can be one of ‘csv’, ‘tsv’, ‘plain’, ‘simple’, ‘grid’, ‘pipe’, ‘orgtbl’, ‘rst’, ‘mediawiki’, ‘latex’, ‘latex_raw’ and ‘latex_booktabs’.