def _csv2rec(fname,
comments='#',
skiprows=0,
checkrows=0,
delimiter=',',
converterd=None,
names=None,
missing='',
missingd=None,
use_mrecords=False,
dayfirst=False,
yearfirst=False):
"""
Load data from comma/space/tab delimited file in *fname* into a
numpy record array and return the record array.
If *names* is *None*, a header row is required to automatically
assign the recarray names. The headers will be lower cased,
spaces will be converted to underscores, and illegal attribute
name characters removed. If *names* is not *None*, it is a
sequence of names to use for the column names. In this case, it
is assumed there is no header row.
- *fname*: can be a filename or a file handle. Support for gzipped
files is automatic, if the filename ends in '.gz'
- *comments*: the character used to indicate the start of a comment
in the file, or *None* to switch off the removal of comments
- *skiprows*: is the number of rows from the top to skip
- *checkrows*: is the number of rows to check to validate the column
data type. When set to zero all rows are validated.
- *converterd*: if not *None*, is a dictionary mapping column number or
munged column name to a converter function.
- *names*: if not None, is a list of header names. In this case, no
header will be read from the file
- *missingd* is a dictionary mapping munged column names to field values
which signify that the field does not contain actual data and should
be masked, e.g., '0000-00-00' or 'unused'
- *missing*: a string whose value signals a missing field regardless of
the column it appears in
- *use_mrecords*: if True, return an mrecords.fromrecords record array if
any of the data are missing
- *dayfirst*: default is False so that MM-DD-YY has precedence over
DD-MM-YY. See
http://labix.org/python-dateutil#head-b95ce2094d189a89f80f5ae52a05b4ab7b41af47
for further information.
- *yearfirst*: default is False so that MM-DD-YY has precedence over
YY-MM-DD. See
http://labix.org/python-dateutil#head-b95ce2094d189a89f80f5ae52a05b4ab7b41af47
for further information.
If no rows are found, *None* is returned
"""
if converterd is None:
converterd = dict()
if missingd is None:
missingd = {}
import dateutil.parser
import datetime
fh = cbook.to_filehandle(fname)
delimiter = str(delimiter)
class FH:
"""
For space-delimited files, we want different behavior than
comma or tab. Generally, we want multiple spaces to be
treated as a single separator, whereas with comma and tab we
want multiple commas to return multiple (empty) fields. The
join/strip trick below effects this.
"""
def __init__(self, fh):
self.fh = fh
def close(self):
self.fh.close()
def seek(self, arg):
self.fh.seek(arg)
def fix(self, s):
return ' '.join(s.split())
def __next__(self):
return self.fix(next(self.fh))
def __iter__(self):
for line in self.fh:
yield self.fix(line)
if delimiter == ' ':
fh = FH(fh)
reader = csv.reader(fh, delimiter=delimiter)
def process_skiprows(reader):
if skiprows:
for i, row in enumerate(reader):
if i >= (skiprows - 1):
break
return fh, reader
process_skiprows(reader)
def ismissing(name, val):
"Should the value val in column name be masked?"
return val == missing or val == missingd.get(name) or val == ''
def with_default_value(func, default):
def newfunc(name, val):
if ismissing(name, val):
return default
else:
return func(val)
return newfunc
def mybool(x):
if x == 'True':
return True
elif x == 'False':
return False
else:
raise ValueError('invalid bool')
dateparser = dateutil.parser.parse
def mydateparser(x):
# try and return a datetime object
d = dateparser(x, dayfirst=dayfirst, yearfirst=yearfirst)
return d
mydateparser = with_default_value(mydateparser, datetime.datetime(1, 1, 1))
myfloat = with_default_value(float, np.nan)
myint = with_default_value(int, -1)
mystr = with_default_value(str, '')
mybool = with_default_value(mybool, None)
def mydate(x):
# try and return a date object
d = dateparser(x, dayfirst=dayfirst, yearfirst=yearfirst)
if d.hour > 0 or d.minute > 0 or d.second > 0:
raise ValueError('not a date')
return d.date()
mydate = with_default_value(mydate, datetime.date(1, 1, 1))
def get_func(name, item, func):
# promote functions in this order
funcs = [mybool, myint, myfloat, mydate, mydateparser, mystr]
for func in funcs[funcs.index(func):]:
try:
func(name, item)
except Exception:
continue
return func
raise ValueError('Could not find a working conversion function')
# map column names that clash with builtins -- TODO - extend this list
itemd = {
'return': 'return_',
'file': 'file_',
'print': 'print_',
}
def get_converters(reader, comments):
converters = None
i = 0
for row in reader:
if (len(row) and comments is not None
and row[0].startswith(comments)):
continue
if i == 0:
converters = [mybool] * len(row)
if checkrows and i > checkrows:
break
i += 1
for j, (name, item) in enumerate(zip(names, row)):
func = converterd.get(j)
if func is None:
func = converterd.get(name)
if func is None:
func = converters[j]
if len(item.strip()):
func = get_func(name, item, func)
else:
# how should we handle custom converters and defaults?
func = with_default_value(func, None)
converters[j] = func
return converters
# Get header and remove invalid characters
needheader = names is None
if needheader:
for row in reader:
if (len(row) and comments is not None
and row[0].startswith(comments)):
continue
headers = row
break
# remove these chars
delete = set(r"""~!@#$%^&*()-=+~\|}[]{';: /?.>,<""")
delete.add('"')
names = []
seen = dict()
for i, item in enumerate(headers):
item = item.strip().lower().replace(' ', '_')
item = ''.join([c for c in item if c not in delete])
if not len(item):
item = 'column%d' % i
item = itemd.get(item, item)
cnt = seen.get(item, 0)
if cnt > 0:
names.append(item + '_%d' % cnt)
else:
names.append(item)
seen[item] = cnt + 1
else:
if isinstance(names, str):
names = [n.strip() for n in names.split(',')]
# get the converter functions by inspecting checkrows
converters = get_converters(reader, comments)
if converters is None:
raise ValueError('Could not find any valid data in CSV file')
# reset the reader and start over
fh.seek(0)
reader = csv.reader(fh, delimiter=delimiter)
process_skiprows(reader)
if needheader:
while True:
# skip past any comments and consume one line of column header
row = next(reader)
if (len(row) and comments is not None
and row[0].startswith(comments)):
continue
break
# iterate over the remaining rows and convert the data to date
# objects, ints, or floats as appropriate
rows = []
rowmasks = []
for i, row in enumerate(reader):
if not len(row):
continue
if comments is not None and row[0].startswith(comments):
continue
# Ensure that the row returned always has the same nr of elements
row.extend([''] * (len(converters) - len(row)))
rows.append([
func(name, val) for func, name, val in zip(converters, names, row)
])
rowmasks.append(
[ismissing(name, val) for name, val in zip(names, row)])
fh.close()
if not len(rows):
return None
if use_mrecords and np.any(rowmasks):
r = np.ma.mrecords.fromrecords(rows, names=names, mask=rowmasks)
else:
r = np.rec.fromrecords(rows, names=names)
return r
def _csv2rec(fname, comments='#', skiprows=0, checkrows=0, delimiter=',',
converterd=None, names=None, missing='', missingd=None,
use_mrecords=False, dayfirst=False, yearfirst=False):
"""
Load data from comma/space/tab delimited file in *fname* into a
numpy record array and return the record array.
If *names* is *None*, a header row is required to automatically
assign the recarray names. The headers will be lower cased,
spaces will be converted to underscores, and illegal attribute
name characters removed. If *names* is not *None*, it is a
sequence of names to use for the column names. In this case, it
is assumed there is no header row.
- *fname*: can be a filename or a file handle. Support for gzipped
files is automatic, if the filename ends in '.gz'
- *comments*: the character used to indicate the start of a comment
in the file, or *None* to switch off the removal of comments
- *skiprows*: is the number of rows from the top to skip
- *checkrows*: is the number of rows to check to validate the column
data type. When set to zero all rows are validated.
- *converterd*: if not *None*, is a dictionary mapping column number or
munged column name to a converter function.
- *names*: if not None, is a list of header names. In this case, no
header will be read from the file
- *missingd* is a dictionary mapping munged column names to field values
which signify that the field does not contain actual data and should
be masked, e.g., '0000-00-00' or 'unused'
- *missing*: a string whose value signals a missing field regardless of
the column it appears in
- *use_mrecords*: if True, return an mrecords.fromrecords record array if
any of the data are missing
- *dayfirst*: default is False so that MM-DD-YY has precedence over
DD-MM-YY. See
http://labix.org/python-dateutil#head-b95ce2094d189a89f80f5ae52a05b4ab7b41af47
for further information.
- *yearfirst*: default is False so that MM-DD-YY has precedence over
YY-MM-DD. See
http://labix.org/python-dateutil#head-b95ce2094d189a89f80f5ae52a05b4ab7b41af47
for further information.
If no rows are found, *None* is returned
"""
if converterd is None:
converterd = dict()
if missingd is None:
missingd = {}
import dateutil.parser
import datetime
fh = cbook.to_filehandle(fname)
delimiter = str(delimiter)
class FH:
"""
For space-delimited files, we want different behavior than
comma or tab. Generally, we want multiple spaces to be
treated as a single separator, whereas with comma and tab we
want multiple commas to return multiple (empty) fields. The
join/strip trick below effects this.
"""
def __init__(self, fh):
self.fh = fh
def close(self):
self.fh.close()
def seek(self, arg):
self.fh.seek(arg)
def fix(self, s):
return ' '.join(s.split())
def __next__(self):
return self.fix(next(self.fh))
def __iter__(self):
for line in self.fh:
yield self.fix(line)
if delimiter == ' ':
fh = FH(fh)
reader = csv.reader(fh, delimiter=delimiter)
def process_skiprows(reader):
if skiprows:
for i, row in enumerate(reader):
if i >= (skiprows-1):
break
return fh, reader
process_skiprows(reader)
def ismissing(name, val):
"Should the value val in column name be masked?"
return val == missing or val == missingd.get(name) or val == ''
def with_default_value(func, default):
def newfunc(name, val):
if ismissing(name, val):
return default
else:
return func(val)
return newfunc
def mybool(x):
if x == 'True':
return True
elif x == 'False':
return False
else:
raise ValueError('invalid bool')
dateparser = dateutil.parser.parse
def mydateparser(x):
# try and return a datetime object
d = dateparser(x, dayfirst=dayfirst, yearfirst=yearfirst)
return d
mydateparser = with_default_value(mydateparser, datetime.datetime(1, 1, 1))
myfloat = with_default_value(float, np.nan)
myint = with_default_value(int, -1)
mystr = with_default_value(str, '')
mybool = with_default_value(mybool, None)
def mydate(x):
# try and return a date object
d = dateparser(x, dayfirst=dayfirst, yearfirst=yearfirst)
if d.hour > 0 or d.minute > 0 or d.second > 0:
raise ValueError('not a date')
return d.date()
mydate = with_default_value(mydate, datetime.date(1, 1, 1))
def get_func(name, item, func):
# promote functions in this order
funcs = [mybool, myint, myfloat, mydate, mydateparser, mystr]
for func in funcs[funcs.index(func):]:
try:
func(name, item)
except Exception:
continue
return func
raise ValueError('Could not find a working conversion function')
# map column names that clash with builtins -- TODO - extend this list
itemd = {
'return': 'return_',
'file': 'file_',
'print': 'print_',
}
def get_converters(reader, comments):
converters = None
i = 0
for row in reader:
if (len(row) and comments is not None and
row[0].startswith(comments)):
continue
if i == 0:
converters = [mybool]*len(row)
if checkrows and i > checkrows:
break
i += 1
for j, (name, item) in enumerate(zip(names, row)):
func = converterd.get(j)
if func is None:
func = converterd.get(name)
if func is None:
func = converters[j]
if len(item.strip()):
func = get_func(name, item, func)
else:
# how should we handle custom converters and defaults?
func = with_default_value(func, None)
converters[j] = func
return converters
# Get header and remove invalid characters
needheader = names is None
if needheader:
for row in reader:
if (len(row) and comments is not None and
row[0].startswith(comments)):
continue
headers = row
break
# remove these chars
delete = set(r"""~!@#$%^&*()-=+~\|}[]{';: /?.>,<""")
delete.add('"')
names = []
seen = dict()
for i, item in enumerate(headers):
item = item.strip().lower().replace(' ', '_')
item = ''.join([c for c in item if c not in delete])
if not len(item):
item = 'column%d' % i
item = itemd.get(item, item)
cnt = seen.get(item, 0)
if cnt > 0:
names.append(item + '_%d' % cnt)
else:
names.append(item)
seen[item] = cnt+1
else:
if isinstance(names, str):
names = [n.strip() for n in names.split(',')]
# get the converter functions by inspecting checkrows
converters = get_converters(reader, comments)
if converters is None:
raise ValueError('Could not find any valid data in CSV file')
# reset the reader and start over
fh.seek(0)
reader = csv.reader(fh, delimiter=delimiter)
process_skiprows(reader)
if needheader:
while True:
# skip past any comments and consume one line of column header
row = next(reader)
if (len(row) and comments is not None and
row[0].startswith(comments)):
continue
break
# iterate over the remaining rows and convert the data to date
# objects, ints, or floats as appropriate
rows = []
rowmasks = []
for i, row in enumerate(reader):
if not len(row):
continue
if comments is not None and row[0].startswith(comments):
continue
# Ensure that the row returned always has the same nr of elements
row.extend([''] * (len(converters) - len(row)))
rows.append([func(name, val)
for func, name, val in zip(converters, names, row)])
rowmasks.append([ismissing(name, val)
for name, val in zip(names, row)])
fh.close()
if not len(rows):
return None
if use_mrecords and np.any(rowmasks):
r = np.ma.mrecords.fromrecords(rows, names=names, mask=rowmasks)
else:
r = np.rec.fromrecords(rows, names=names)
return r
