updated from Atlas

attic/sequences/str_concat.py

@@ -0,0 +1,43 @@
+"""string concatenation demos"""
+
+from time import perf_counter
+
+def load_lines():
+    with open('war-and-peace.txt') as fp:
+        return fp.readlines() * 100  # replace with 200 or more for surprises!!!
+
+def chrono(f):
+    def inner(lines):
+        t0 = perf_counter()
+        text = f(lines)
+        elapsed = perf_counter() - t0
+        print('%15s: %fs' % (f.__name__, elapsed))
+        return text
+    return inner
+
+@chrono
+def iadd_joiner(lines):
+    text = ''
+    for line in lines:
+        text += line
+    return text
+
+@chrono
+def list_joiner(lines):
+    parts = []
+    for line in lines:
+        parts.append(line)
+    return ''.join(parts)
+
+@chrono
+def genexp_joiner(lines):
+    return ''.join(line for line in lines)
+
+if __name__=='__main__':
+    lines = load_lines()
+    print('joining %s lines' % len(lines))
+    text0 = iadd_joiner(lines)
+    text1 = list_joiner(lines)
+    text2 = genexp_joiner(lines)
+    assert len(text0) == len(text1) == len(text2), repr(
+        (len(text0), len(text1), len(text2)))