diff options
Diffstat (limited to 'numpy/lib/io.py')
| -rw-r--r-- | numpy/lib/io.py | 66 |
1 files changed, 42 insertions, 24 deletions
diff --git a/numpy/lib/io.py b/numpy/lib/io.py index e0b83d89b..ec3f39cc2 100644 --- a/numpy/lib/io.py +++ b/numpy/lib/io.py @@ -306,9 +306,11 @@ def save(file, arr): Parameters ---------- - file : file or string - File or filename to which the data is saved. If the filename - does not already have a ``.npy`` extension, it is added. + file : file or str + File or filename to which the data is saved. If file is a file-object, + then the filename is unchanged. If file is a string, a ``.npy`` + extension will be appended to the file name if it does not already + have one. arr : array_like Array data to be saved. @@ -329,7 +331,7 @@ def save(file, arr): >>> x = np.arange(10) >>> np.save(outfile, x) - >>> outfile.seek(0) # only necessary in this example (with tempfile) + >>> outfile.seek(0) # Only needed here to simulate closing & reopening file >>> np.load(outfile) array([0, 1, 2, 3, 4, 5, 6, 7, 8, 9]) @@ -348,25 +350,29 @@ def savez(file, *args, **kwds): """ Save several arrays into a single, compressed file in ``.npz`` format. - If keyword arguments are given, the names for variables assigned to the - keywords are the keyword names (not the variable names in the caller). If arguments are passed in with no keywords, the corresponding variable - names are arr_0, arr_1, etc. + names, in the .npz file, are 'arr_0', 'arr_1', etc. If keyword arguments + are given, the corresponding variable names, in the ``.npz`` file will + match the keyword names. Parameters ---------- file : str or file Either the file name (string) or an open file (file-like object) - If file is a string, it names the output file. ".npz" will be appended - to the file name if it is not already there. - args : Arguments - Any function arguments other than the file name are variables to save. - Since it is not possible for Python to know their names outside - `savez`, they will be saved with names "arr_0", "arr_1", and so on. - These arguments can be any expression. - kwds : Keyword arguments - All keyword=value pairs cause the value to be saved with the name of - the keyword. + where the data will be saved. If file is a string, the ``.npz`` + extension will be appended to the file name if it is not already there. + \\*args : Arguments, optional + Arrays to save to the file. Since it is not possible for Python to + know the names of the arrays outside `savez`, the arrays will be saved + with names "arr_0", "arr_1", and so on. These arguments can be any + expression. + \\*\\*kwds : Keyword arguments, optional + Arrays to save to the file. Arrays will be saved in the file with the + keyword names. + + Returns + ------- + None See Also -------- @@ -379,6 +385,11 @@ def savez(file, *args, **kwds): variables they contain. Each file contains one variable in ``.npy`` format. For a description of the ``.npy`` format, see `format`. + When opening the saved ``.npz`` file with `load` a `NpzFile` object is + returned. This is a dictionary-like object which can be queried for + its list of arrays (with the ``.files`` attribute), and for the arrays + themselves. + Examples -------- >>> from tempfile import TemporaryFile @@ -389,11 +400,11 @@ def savez(file, *args, **kwds): Using `savez` with \\*args, the arrays are saved with default names. >>> np.savez(outfile, x, y) - >>> outfile.seek(0) # only necessary in this example (with tempfile) - >>> npz = np.load(outfile) - >>> npz.files + >>> outfile.seek(0) # Only needed here to simulate closing & reopening file + >>> npzfile = np.load(outfile) + >>> npzfile.files ['arr_1', 'arr_0'] - >>> npz['arr_0'] + >>> npzfile['arr_0'] array([0, 1, 2, 3, 4, 5, 6, 7, 8, 9]) Using `savez` with \\*\\*kwds, the arrays are saved with the keyword names. @@ -401,10 +412,10 @@ def savez(file, *args, **kwds): >>> outfile = TemporaryFile() >>> np.savez(outfile, x=x, y=y) >>> outfile.seek(0) - >>> npz = np.load(outfile) - >>> npz.files + >>> npzfile = np.load(outfile) + >>> npzfile.files ['y', 'x'] - >>> npz['x'] + >>> npzfile['x'] array([0, 1, 2, 3, 4, 5, 6, 7, 8, 9]) """ @@ -510,8 +521,15 @@ def loadtxt(fname, dtype=float, comments='#', delimiter=None, converters=None, See Also -------- load, fromstring, fromregex + genfromtxt : Load data with missing values handled as specified. scipy.io.loadmat : reads Matlab(R) data files + Notes + ----- + This function aims to be a fast reader for simply formatted files. The + `genfromtxt` function provides more sophisticated handling of, e.g., + lines with missing values. + Examples -------- >>> from StringIO import StringIO # StringIO behaves like a file object |