Update read-n-characters-given-read4.py

NYCGithub · web-flow · commit 65cf9499302d · 2018-08-02T22:53:50.000-04:00
Your original code will not behave correctly if the input is "abcd", and n = 3. It'll save "abcd" to the buffer, where it should save only "abc" into buffer. The modification will allow it to do so.
diff --git a/Python/read-n-characters-given-read4.py b/Python/read-n-characters-given-read4.py
@@ -37,14 +37,17 @@ def read(self, buf, n):
         """
         read_bytes = 0
         buffer = [''] * 4
+        globalN = n
         for i in xrange(n / 4 + 1):
             size = read4(buffer)
             if size:
-                buf[read_bytes:read_bytes+size] = buffer
-                read_bytes += size
+                toRead = min(globalN,size)
+                buf[read_bytes:read_bytes+toRead] = buffer
+                read_bytes += toRead
+                globalN -= toRead
             else:
                 break
-        return min(read_bytes, n)
+        return read_bytes
 
 if __name__ == "__main__":
     global file_content
