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Add loadtxt and savetxt adapted from matplotlib.

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1 parent 41861b5 commit fcb7fd261eb0e73fb8abba78e692aca0ba00ce82 @teoliphant teoliphant committed Apr 22, 2007
Showing with 175 additions and 4 deletions.
  1. +3 −3 COMPATIBILITY
  2. +172 −1 numpy/core/numeric.py
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@@ -15,7 +15,7 @@ but always 1-d) --- only has .copy and .__array__ attributes of an array!!!
If you used typecode characters:
-'c' -> 'S1'
+'c' -> 'S1' or 'c'
'b' -> 'B'
'1' -> 'b'
's' -> 'h'
@@ -35,12 +35,12 @@ using PyMemData_FREE(ptr);
a->descr->zero --> PyArray_Zero(a)
a->descr->one --> PyArray_One(a)
-Numeric/arrayobject.h --> numpy/arrayobject.h
+Numeric/arrayobject.h --> numpy/oldnumeric.h
# These will actually work and are defines for PyArray_BYTE,
# but you really should change it in your code
-PyArray_CHAR --> PyArray_BYTE
+PyArray_CHAR --> PyArray_CHAR
(or PyArray_STRING which is more flexible)
PyArray_SBYTE --> PyArray_BYTE
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@@ -12,7 +12,7 @@
'array_repr', 'array_str', 'set_string_function',
'little_endian', 'require',
'fromiter', 'array_equal', 'array_equiv',
- 'indices', 'fromfunction',
+ 'indices', 'fromfunction', 'loadtxt', 'savetxt',
'load', 'loads', 'isscalar', 'binary_repr', 'base_repr',
'ones', 'identity', 'allclose', 'compare_chararrays', 'putmask',
'seterr', 'geterr', 'setbufsize', 'getbufsize',
@@ -610,6 +610,177 @@ def load(file):
file = _file(file,"rb")
return _cload(file)
+# Adapted from matplotlib
+
+def _getconv(dtype):
+ typ = dtype.type
+ if issubclass(typ, bool_):
+ return lambda x: bool(int(x))
+ if issubclass(typ, integer):
+ return int
+ elif issubclass(typ, floating):
+ return float
+ elif issubclass(typ, complex):
+ return complex
+ else:
+ return str
+
+
+def _string_like(obj):
+ try: obj + ''
+ except (TypeError, ValueError): return 0
+ return 1
+
+def loadtxt(fname, dtype=float, comments='#', delimiter=None, converters=None,
+ skiprows=0, usecols=None, unpack=False):
+ """
+ Load ASCII data from fname into an array and return the array.
+
+ The data must be regular, same number of values in every row
+
+ fname can be a filename or a file handle. Support for gzipped files is
+ automatic, if the filename ends in .gz
+
+ See scipy.loadmat to read and write matfiles.
+
+ Example usage:
+
+ X = loadtxt('test.dat') # data in two columns
+ t = X[:,0]
+ y = X[:,1]
+
+ Alternatively, you can do the same with "unpack"; see below
+
+ X = loadtxt('test.dat') # a matrix of data
+ x = loadtxt('test.dat') # a single column of data
+
+
+ dtype - the data-type of the resulting array. If this is a
+ record data-type, the the resulting array will be 1-d and each row will
+ be interpreted as an element of the array. The number of columns
+ used must match the number of fields in the data-type in this case.
+
+ comments - the character used to indicate the start of a comment
+ in the file
+
+ delimiter is a string-like character used to seperate values in the
+ file. If delimiter is unspecified or none, any whitespace string is
+ a separator.
+
+ converters, if not None, is a dictionary mapping column number to
+ a function that will convert that column to a float. Eg, if
+ column 0 is a date string: converters={0:datestr2num}
+
+ skiprows is the number of rows from the top to skip
+
+ usecols, if not None, is a sequence of integer column indexes to
+ extract where 0 is the first column, eg usecols=(1,4,5) to extract
+ just the 2nd, 5th and 6th columns
+
+ unpack, if True, will transpose the matrix allowing you to unpack
+ into named arguments on the left hand side
+
+ t,y = load('test.dat', unpack=True) # for two column data
+ x,y,z = load('somefile.dat', usecols=(3,5,7), unpack=True)
+
+ """
+
+ if _string_like(fname):
+ if fname.endswith('.gz'):
+ import gzip
+ fh = gzip.open(fname)
+ else:
+ fh = file(fname)
+ elif hasattr(fname, 'seek'):
+ fh = fname
+ else:
+ raise ValueError('fname must be a string or file handle')
+ X = []
+
+ dtype = multiarray.dtype(dtype)
+ defconv = _getconv(dtype)
+ converterseq = None
+ if converters is None:
+ converters = {}
+ if dtype.names is not None:
+ converterseq = [_getconv(dtype.fields[name][0]) \
+ for name in dtype.names]
+
+ for i,line in enumerate(fh):
+ if i<skiprows: continue
+ line = line[:line.find(comments)].strip()
+ if not len(line): continue
+ vals = line.split(delimiter)
+ if converterseq is None:
+ converterseq = [converters.get(j,defconv) \
+ for j in xrange(len(vals))]
+ if usecols is not None:
+ row = [converterseq[j](vals[j]) for j in usecols]
+ else:
+ row = [converterseq[j](val) for j,val in enumerate(vals)]
+ if dtype.names is not None:
+ row = tuple(row)
+ X.append(row)
+
+ X = array(X, dtype)
+ r,c = X.shape
+ if r==1 or c==1:
+ X.shape = max([r,c]),
+ if unpack: return X.T
+ else: return X
+
+
+# adjust so that fmt can change across columns if desired.
+
+def savetxt(fname, X, fmt='%.18e',delimiter=' '):
+ """
+ Save the data in X to file fname using fmt string to convert the
+ data to strings
+
+ fname can be a filename or a file handle. If the filename ends in .gz,
+ the file is automatically saved in compressed gzip format. The load()
+ command understands gzipped files transparently.
+
+ Example usage:
+
+ save('test.out', X) # X is an array
+ save('test1.out', (x,y,z)) # x,y,z equal sized 1D arrays
+ save('test2.out', x) # x is 1D
+ save('test3.out', x, fmt='%1.4e') # use exponential notation
+
+ delimiter is used to separate the fields, eg delimiter ',' for
+ comma-separated values
+ """
+
+ if _string_like(fname):
+ if fname.endswith('.gz'):
+ import gzip
+ fh = gzip.open(fname,'wb')
+ else:
+ fh = file(fname,'w')
+ elif hasattr(fname, 'seek'):
+ fh = fname
+ else:
+ raise ValueError('fname must be a string or file handle')
+
+
+ X = asarray(X)
+ origShape = None
+ if len(X.shape)==1:
+ origShape = X.shape
+ X.shape = len(X), 1
+ for row in X:
+ fh.write(delimiter.join([fmt%val for val in row]) + '\n')
+
+ if origShape is not None:
+ X.shape = origShape
+
+
+
+
+
+
+
# These are all essentially abbreviations
# These might wind up in a special abbreviations module

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