Source code for sas.sascalc.dataloader.readers.ascii_reader

"""
    Generic multi-column ASCII data reader
"""
############################################################################
# This software was developed by the University of Tennessee as part of the
# Distributed Data Analysis of Neutron Scattering Experiments (DANSE)
# project funded by the US National Science Foundation.
# If you use DANSE applications to do scientific research that leads to
# publication, we ask that you acknowledge the use of the software with the
# following sentence:
# This work benefited from DANSE software developed under NSF award DMR-0520547.
# copyright 2008, University of Tennessee
#############################################################################

import logging
from sas.sascalc.dataloader.file_reader_base_class import FileReader
from sas.sascalc.dataloader.data_info import DataInfo, plottable_1D
from sas.sascalc.dataloader.loader_exceptions import FileContentsException,\
    DefaultReaderException

logger = logging.getLogger(__name__)


[docs]class Reader(FileReader): """ Class to load ascii files (2, 3 or 4 columns). """ # File type type_name = "ASCII" # Wildcards type = ["ASCII files (*.txt)|*.txt", "ASCII files (*.dat)|*.dat", "ASCII files (*.abs)|*.abs", "CSV files (*.csv)|*.csv"] # List of allowed extensions ext = ['.txt', '.dat', '.abs', '.csv'] # Flag to bypass extension check allow_all = True # data unless that is the only data min_data_pts = 5
[docs] def get_file_contents(self): """ Get the contents of the file """ buff = self.readall() filepath = self.f_open.name lines = buff.splitlines() self.output = [] self.current_datainfo = DataInfo() self.current_datainfo.filename = filepath self.reset_data_list(len(lines)) # The first good line of data will define whether # we have 2-column or 3-column ascii has_error_dx = None has_error_dy = None # Initialize counters for data lines and header lines. is_data = False # More than "5" lines of data is considered as actual # To count # of current data candidate lines candidate_lines = 0 # To count total # of previous data candidate lines candidate_lines_previous = 0 # Current line number line_no = 0 # minimum required number of columns of data lentoks = 2 for line in lines: toks = self.splitline(line.strip()) # To remember the number of columns in the current line of data new_lentoks = len(toks) try: if new_lentoks == 0: # If the line is blank, skip and continue on # In case of breaks within data sets. continue elif new_lentoks != lentoks and is_data: # If a footer is found, break the loop and save the data break elif new_lentoks != lentoks and not is_data: # If header lines are numerical candidate_lines = 0 self.reset_data_list(len(lines) - line_no) self.current_dataset.x[candidate_lines] = float(toks[0]) if new_lentoks > 1: self.current_dataset.y[candidate_lines] = float(toks[1]) # If a 3rd row is present, consider it dy if new_lentoks > 2: self.current_dataset.dy[candidate_lines] = \ float(toks[2]) has_error_dy = True # If a 4th row is present, consider it dx if new_lentoks > 3: self.current_dataset.dx[candidate_lines] = \ float(toks[3]) has_error_dx = True candidate_lines += 1 # If 5 or more lines, this is considering the set data if candidate_lines >= self.min_data_pts: is_data = True if is_data and new_lentoks >= 8: msg = "This data looks like 2D ASCII data. Use the file " msg += "converter tool to convert it to NXcanSAS." raise FileContentsException(msg) # To remember the # of columns on the current line # for the next line of data lentoks = new_lentoks line_no += 1 except ValueError: # ValueError is raised when non numeric strings conv. to float # It is data and meet non - number, then stop reading if is_data: break # Delete the previously stored lines of data candidates if # the list is not data self.reset_data_list(len(lines) - line_no) lentoks = 2 has_error_dx = None has_error_dy = None # Reset # of lines of data candidates candidate_lines = 0 if not is_data: self.set_all_to_none() if self.extension in self.ext: msg = "ASCII Reader error: Fewer than five Q data points found " msg += "in {}.".format(filepath) raise FileContentsException(msg) else: msg = "ASCII Reader could not load the file {}".format(filepath) raise DefaultReaderException(msg) # Sanity check if has_error_dy and not len(self.current_dataset.y) == \ len(self.current_dataset.dy): msg = "ASCII Reader error: Number of I and dI data points are" msg += " different in {}.".format(filepath) # TODO: Add error to self.current_datainfo.errors instead? self.set_all_to_none() raise FileContentsException(msg) if has_error_dx and not len(self.current_dataset.x) == \ len(self.current_dataset.dx): msg = "ASCII Reader error: Number of Q and dQ data points are" msg += " different in {}.".format(filepath) # TODO: Add error to self.current_datainfo.errors instead? self.set_all_to_none() raise FileContentsException(msg) self.remove_empty_q_values() self.current_dataset = self.set_default_1d_units(self.current_dataset) # Store loading process information self.current_datainfo.meta_data['loader'] = self.type_name self.send_to_output()