Add rgb_to_hex snippet

snippets/rgb_to_hex.md

@@ -0,0 +1,18 @@
+---
+title: rgb_to_hex
+tags: string,math,intermediate
+---
+
+Converts the values of RGB components to a hexadecimal color code.
+
+Create a placeholder for a zero-padded hexadecimal value using `"{:02X}"`, copy it three times.
+Use `str.format()` on the resulting string to replace the placeholders with the given values.
+
+```py
+def rgb_to_hex(r, g, b):
+  return ("{:02X}" * 3).format(r, g, b)
+```
+
+```py
+rgb_to_hex(255, 165, 1) # 'FFA501'
+```