From db08acf3e4e0f696a42164613b7342a1be0912f5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jon=20Haitz=20Legarreta=20Gorro=C3=B1o?=
 <jon.haitz.legarreta@gmail.com>
Date: Sat, 5 Jul 2025 17:50:49 -0400
Subject: [PATCH] STYLE: Call `write` once instead of looping

Call `write` once instead of looping by concatenating all strings that
need to be written.

Avoid using `writelines` as `ImageOpener` objects do not have that
attribute.

Fixes:
```
-                for val in bvals:
-                    fid.write(f'{val} ')
+                fid.writelines(f'{val} ' for val in bvals)
```

and other similar errors raised for example in:
https://github.com/nipy/nibabel/actions/runs/16092302666/job/45410655457?pr=1422#step:7:23

Documentation:
https://docs.astral.sh/ruff/rules/for-loop-writes/
---
 nibabel/cmdline/parrec2nii.py | 9 +++------
 nibabel/volumeutils.py        | 3 +--
 2 files changed, 4 insertions(+), 8 deletions(-)

diff --git a/nibabel/cmdline/parrec2nii.py b/nibabel/cmdline/parrec2nii.py
index 0ae6b3fb4..aa8861042 100644
--- a/nibabel/cmdline/parrec2nii.py
+++ b/nibabel/cmdline/parrec2nii.py
@@ -358,8 +358,7 @@ def proc_file(infile, opts):
             )
             with open(basefilename + '.bvals', 'w') as fid:
                 # np.savetxt could do this, but it's just a loop anyway
-                for val in bvals:
-                    fid.write(f'{val} ')
+                fid.write(' '.join(str(val) for val in bvals) + ' ')
                 fid.write('\n')
         else:
             verbose('Writing .bvals and .bvecs files')
@@ -369,13 +368,11 @@ def proc_file(infile, opts):
             bvecs = apply_affine(bv_reorient, bvecs)
             with open(basefilename + '.bvals', 'w') as fid:
                 # np.savetxt could do this, but it's just a loop anyway
-                for val in bvals:
-                    fid.write(f'{val} ')
+                fid.write(' '.join(str(val) for val in bvals) + ' ')
                 fid.write('\n')
             with open(basefilename + '.bvecs', 'w') as fid:
                 for row in bvecs.T:
-                    for val in row:
-                        fid.write(f'{val} ')
+                    fid.write(' '.join(str(val) for val in row) + ' ')
                     fid.write('\n')
 
     # export data labels varying along the 4th dimensions if requested
diff --git a/nibabel/volumeutils.py b/nibabel/volumeutils.py
index 41bff7275..c5ebbdd2c 100644
--- a/nibabel/volumeutils.py
+++ b/nibabel/volumeutils.py
@@ -830,8 +830,7 @@ def write_zeros(fileobj: io.IOBase, count: int, block_size: int = 8194) -> None:
     nblocks = int(count // block_size)
     rem = count % block_size
     blk = b'\x00' * block_size
-    for bno in range(nblocks):
-        fileobj.write(blk)
+    fileobj.write(blk * nblocks)
     fileobj.write(b'\x00' * rem)