Added write_csv function to export a dataset to regular comma/tab/whatever separated files.

laydi/dataset.py

@@ -707,6 +707,50 @@ def read_ftsv(fd, sep=None):
 
     return ds
 
+def write_csv(fd, ds, decimals=7, sep='\t'):
+    """Write a dataset as comma/tab/whatever dilimited data.
+    
+    @param fd: An open file descriptor to the output file.
+    @param ds: The dataset to be written. 
+    @param decimals: Number of decimals, only supported for dataset.
+    @param sep: Value separator
+    """
+
+    ## Open file if a string is passed instead of a file descriptor
+    opened = False
+    if isinstance(fd, str):
+        fd = open(fd, 'w')
+        opened = True
+    
+    ## Get data
+    rowdim, coldim = ds.get_dim_name()
+    rowids = ds.get_identifiers(rowdim)
+    colids = ds.get_identifiers(coldim)
+    a = ds.asarray()
+    y, x = a.shape
+    fmt = '%%%if' % decimals
+
+    ## Write header
+    fd.write(rowdim)
+    fd.write(sep)
+    for i, id in enumerate(colids):
+        fd.write(id)
+        fd.write(sep)
+    fd.write('\n')
+
+    ## Write matrix data
+    for j in range(y):
+        fd.write(rowids[j])
+        fd.write(sep)
+        for i in range(x):
+            fd.write(fmt % (a[j, i],))
+            fd.write(sep)
+        fd.write('\n')
+    
+    ## If we opened the stream, close it
+    if opened:
+        fd.close()
+
 def _write_sparse_elements(fd, arr, fmt='%d', sep=None):
     """ Sparse coordinate format.""" 
     fd.write('# sp_format: True\n\n')