Replace inline comments with docstrings (#12764)

* Add docstrings

* Add docstrings

* Add docstrings

* Add docstrings

* Add docstrings

* Add docstrings

* Add docstrings

* Add docstrings

* Add docstrings

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* Add docstrings

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* Update plots.py

Signed-off-by: Glenn Jocher <glenn.jocher@ultralytics.com>

---------

Signed-off-by: Glenn Jocher <glenn.jocher@ultralytics.com>
Co-authored-by: UltralyticsAssistant <web@ultralytics.com>

utils/plots.py

@@ -67,7 +67,8 @@ class Colors:
         return (c[2], c[1], c[0]) if bgr else c
 
     @staticmethod
-    def hex2rgb(h):  # rgb order (PIL)
+    def hex2rgb(h):
+        """Converts hexadecimal color `h` to an RGB tuple (PIL-compatible) with order (R, G, B)."""
         return tuple(int(h[1 + i : 1 + i + 2], 16) for i in (0, 2, 4))
 
 
@@ -225,8 +226,13 @@ def plot_lr_scheduler(optimizer, scheduler, epochs=300, save_dir=""):
     plt.close()
 
 
-def plot_val_txt():  # from utils.plots import *; plot_val()
-    # Plot val.txt histograms
+def plot_val_txt():
+    """
+    Plots 2D and 1D histograms of bounding box centers from 'val.txt' using matplotlib, saving as 'hist2d.png' and
+    'hist1d.png'.
+
+    Example: from utils.plots import *; plot_val()
+    """
     x = np.loadtxt("val.txt", dtype=np.float32)
     box = xyxy2xywh(x[:, :4])
     cx, cy = box[:, 0], box[:, 1]
@@ -242,8 +248,12 @@ def plot_val_txt():  # from utils.plots import *; plot_val()
     plt.savefig("hist1d.png", dpi=200)
 
 
-def plot_targets_txt():  # from utils.plots import *; plot_targets_txt()
-    # Plot targets.txt histograms
+def plot_targets_txt():
+    """
+    Plots histograms of object detection targets from 'targets.txt', saving the figure as 'targets.jpg'.
+
+    Example: from utils.plots import *; plot_targets_txt()
+    """
     x = np.loadtxt("targets.txt", dtype=np.float32).T
     s = ["x targets", "y targets", "width targets", "height targets"]
     fig, ax = plt.subplots(2, 2, figsize=(8, 8), tight_layout=True)
@@ -255,8 +265,13 @@ def plot_targets_txt():  # from utils.plots import *; plot_targets_txt()
     plt.savefig("targets.jpg", dpi=200)
 
 
-def plot_val_study(file="", dir="", x=None):  # from utils.plots import *; plot_val_study()
-    # Plot file=study.txt generated by val.py (or plot all study*.txt in dir)
+def plot_val_study(file="", dir="", x=None):
+    """
+    Plots validation study results from 'study*.txt' files in a directory or a specific file, comparing model
+    performance and speed.
+
+    Example: from utils.plots import *; plot_val_study()
+    """
     save_dir = Path(file).parent if file else Path(dir)
     plot2 = False  # plot additional results
     if plot2:
@@ -381,8 +396,12 @@ def imshow_cls(im, labels=None, pred=None, names=None, nmax=25, verbose=False, f
     return f
 
 
-def plot_evolve(evolve_csv="path/to/evolve.csv"):  # from utils.plots import *; plot_evolve()
-    # Plot evolve.csv hyp evolution results
+def plot_evolve(evolve_csv="path/to/evolve.csv"):
+    """
+    Plots hyperparameter evolution results from a given CSV, saving the plot and displaying best results.
+
+    Example: from utils.plots import *; plot_evolve()
+    """
     evolve_csv = Path(evolve_csv)
     data = pd.read_csv(evolve_csv)
     keys = [x.strip() for x in data.columns]