1 files changed, 52 insertions, 0 deletions
diff --git a/examples/redirect_print.py b/examples/redirect_print.py
new file mode 100644
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--- /dev/null
+++ b/examples/redirect_print.py
@@ -0,0 +1,52 @@
+"""Redirecting writing
+
+If using a library that can print messages to the console, editing the library
+by  replacing `print()` with `tqdm.write()` may not be desirable.
+In that case, redirecting `sys.stdout` to `tqdm.write()` is an option.
+
+To redirect `sys.stdout`, create a file-like class that will write
+any input string to `tqdm.write()`, and supply the arguments
+`file=sys.stdout, dynamic_ncols=True`.
+
+A reusable canonical example is given below:
+"""
+from __future__ import print_function
+
+import contextlib
+import sys
+from time import sleep
+
+from tqdm import tqdm
+from tqdm.contrib import DummyTqdmFile
+
+
+@contextlib.contextmanager
+def std_out_err_redirect_tqdm():
+    orig_out_err = sys.stdout, sys.stderr
+    try:
+        # sys.stdout = sys.stderr = DummyTqdmFile(orig_out_err[0])
+        sys.stdout, sys.stderr = map(DummyTqdmFile, orig_out_err)
+        yield orig_out_err[0]
+    # Relay exceptions
+    except Exception as exc:
+        raise exc
+    # Always restore sys.stdout/err if necessary
+    finally:
+        sys.stdout, sys.stderr = orig_out_err
+
+
+def some_fun(i):
+    print("Fee, fi, fo,".split()[i])
+
+
+# Redirect stdout to tqdm.write()
+with std_out_err_redirect_tqdm() as orig_stdout:
+    # tqdm needs the original stdout
+    # and dynamic_ncols=True to autodetect console width
+    for i in tqdm(range(3), file=orig_stdout, dynamic_ncols=True):
+        # order of the following two lines should not matter
+        some_fun(i)
+        sleep(.5)
+
+# After the `with`, printing is restored
+print("Done!")