vfdev-5: @miguelvr thanks for the review ! 
diff --git a/ignite/contrib/handlers/tqdm_logger.py b/ignite/contrib/handlers/tqdm_logger.py
index b2d41e6b..9e18f420 100644
--- a/ignite/contrib/handlers/tqdm_logger.py
+++ b/ignite/contrib/handlers/tqdm_logger.py
@@ -1,5 +1,4 @@
 # -*- coding: utf-8 -*-
-import numbers
 import warnings
 
 import torch
@@ -53,7 +52,7 @@ class ProgressBar(BaseLogger):
             pbar.attach(trainer, ['loss'])
 
             # Progress bar will looks like
-            # Epoch [2/50]: [64/128]  50%|█████      , loss=12.34e-02 [06:17<12:34]
+            # Epoch [2/50]: [64/128]  50%|█████      , loss=0.123 [06:17<12:34]
 
         Directly attach the engine's output
 
@@ -65,7 +64,7 @@ class ProgressBar(BaseLogger):
             pbar.attach(trainer, output_transform=lambda x: {'loss': x})
 
             # Progress bar will looks like
-            # Epoch [2/50]: [64/128]  50%|█████      , loss=12.34e-02 [06:17<12:34]
+            # Epoch [2/50]: [64/128]  50%|█████      , loss=0.123 [06:17<12:34]
 
     Note:
         When adding attaching the progress bar to an engine, it is recommend that you replace
@@ -91,6 +90,7 @@ class ProgressBar(BaseLogger):
 
     def __init__(self, persist=False,
                  bar_format='{desc}[{n_fmt}/{total_fmt}] {percentage:3.0f}%|{bar}{postfix} [{elapsed}<{remaining}]',
+
                  **tqdm_kwargs):
 
         try:
@@ -226,18 +226,18 @@ class _OutputHandler(BaseOutputHandler):
 
         rendered_metrics = {}
         for key, value in metrics.items():
-            if isinstance(value, numbers.Number) or \
-                    isinstance(value, torch.Tensor) and value.ndimension() == 0:
-                rendered_metrics[key] = "{:.2e}".format(value)
-            elif isinstance(value, torch.Tensor) and value.ndimension() == 1:
-                for i, v in enumerate(value):
-                    k = "{}_{}".format(key, i)
-                    rendered_metrics[k] = "{:.2e}".format(v)
-            elif isinstance(value, str):
-                rendered_metrics[key] = value
+            if isinstance(value, torch.Tensor):
+                if value.ndimension() == 0:
+                    rendered_metrics[key] = value.item()
+                elif value.ndimension() == 1:
+                    for i, v in enumerate(value):
+                        k = "{}_{}".format(key, i)
+                        rendered_metrics[k] = v.item()
+                else:
+                    warnings.warn("ProgressBar can not log "
+                                  "tensor with {} dimensions".format(value.ndimension()))
             else:
-                warnings.warn("ProgressBar can not log "
-                              "metrics value type {}".format(type(value)))
+                rendered_metrics[key] = value
 
         if rendered_metrics:
             logger.pbar.set_postfix(**rendered_metrics)

Improve TQDM, progress bar value formatting
Idea is to use tqdm's value renderer instead of using current implementation. Newer version will looks like:
```python
import tqdm
with tqdm.tqdm() as pbar:
    pbar.set_postfix({'a': 123, 'b': 12.3456788, 'd': 0.12345, 'c': torch.tensor(123).item(), 'e': 'text', 'f': lambda x: x})
```
out:
```
0it [00:00, ?it/s, a=123, b=12.3, d=0.123, c=123, e=text, f=<function <lambda> at 0x1234>]
```

This will help to better display integer values as `123` instead of `1.23e+02`.

cc @miguelvr 
diff --git a/tests/ignite/contrib/handlers/test_tqdm_logger.py b/tests/ignite/contrib/handlers/test_tqdm_logger.py
index f5d8b0fa..b6fd4f1d 100644
--- a/tests/ignite/contrib/handlers/test_tqdm_logger.py
+++ b/tests/ignite/contrib/handlers/test_tqdm_logger.py
@@ -31,7 +31,7 @@ def test_pbar(capsys):
     err = captured.err.split('\r')
     err = list(map(lambda x: x.strip(), err))
     err = list(filter(None, err))
-    expected = u'Epoch [2/2]: [1/2]  50%|█████     , a=1.00e+00 [00:00<00:00]'
+    expected = u'Epoch [2/2]: [1/2]  50%|█████     , a=1 [00:00<00:00]'
     assert err[-1] == expected
 
 
@@ -79,7 +79,7 @@ def test_pbar_with_metric(capsys):
     err = list(map(lambda x: x.strip(), err))
     err = list(filter(None, err))
     actual = err[-1]
-    expected = u'Epoch: [1/2]  50%|█████     , batchloss=5.00e-01 [00:00<00:00]'
+    expected = u'Epoch: [1/2]  50%|█████     , batchloss=0.5 [00:00<00:00]'
     assert actual == expected
 
 
@@ -110,7 +110,7 @@ def test_pbar_with_all_metric(capsys):
     err = list(map(lambda x: x.strip(), err))
     err = list(filter(None, err))
     actual = err[-1]
-    expected = u'Epoch: [1/2]  50%|█████     , another batchloss=1.50e+00, batchloss=5.00e-01 [00:00<00:00]'
+    expected = u'Epoch: [1/2]  50%|█████     , another batchloss=1.5, batchloss=0.5 [00:00<00:00]'
     assert actual == expected
 
 
@@ -148,7 +148,7 @@ def test_pbar_with_output(capsys):
     err = captured.err.split('\r')
     err = list(map(lambda x: x.strip(), err))
     err = list(filter(None, err))
-    expected = u'Epoch [2/2]: [1/2]  50%|█████     , a=1.00e+00 [00:00<00:00]'
+    expected = u'Epoch [2/2]: [1/2]  50%|█████     , a=1 [00:00<00:00]'
     assert err[-1] == expected
 
 
@@ -174,7 +174,7 @@ def test_pbar_with_scalar_output(capsys):
     err = captured.err.split('\r')
     err = list(map(lambda x: x.strip(), err))
     err = list(filter(None, err))
-    expected = u'Epoch [2/2]: [1/2]  50%|█████     , output=1.00e+00 [00:00<00:00]'
+    expected = u'Epoch [2/2]: [1/2]  50%|█████     , output=1 [00:00<00:00]'
     assert err[-1] == expected
 
 
@@ -209,7 +209,7 @@ def test_pbar_with_tqdm_kwargs(capsys):
     err = captured.err.split('\r')
     err = list(map(lambda x: x.strip(), err))
     err = list(filter(None, err))
-    expected = u'My description:  [10/10]: [4/5]  80%|████████  , output=1.00e+00 [00:00<00:00]'.format()
+    expected = u'My description:  [10/10]: [4/5]  80%|████████  , output=1 [00:00<00:00]'.format()
     assert err[-1] == expected
 
 
@@ -230,30 +230,36 @@ def test_pbar_for_validation(capsys):
 
 
 def test_pbar_output_tensor(capsys):
-    loader = [1, 2, 3, 4, 5]
 
-    def update_fn(engine, batch):
-        return torch.Tensor([batch, 0])
+    def _test(out_tensor, out_msg):
+        loader = [1, 2, 3, 4, 5]
 
-    engine = Engine(update_fn)
+        def update_fn(engine, batch):
+            return out_tensor
 
-    pbar = ProgressBar(desc="Output tensor")
-    pbar.attach(engine, output_transform=lambda x: x)
-    engine.run(loader, max_epochs=1)
+        engine = Engine(update_fn)
 
-    captured = capsys.readouterr()
-    err = captured.err.split('\r')
-    err = list(map(lambda x: x.strip(), err))
-    err = list(filter(None, err))
-    expected = u'Output tensor: [4/5]  80%|████████  , output_0=5.00e+00, output_1=0.00e+00 [00:00<00:00]'
-    assert err[-1] == expected
+        pbar = ProgressBar(desc="Output tensor")
+        pbar.attach(engine, output_transform=lambda x: x)
+        engine.run(loader, max_epochs=1)
+
+        captured = capsys.readouterr()
+        err = captured.err.split('\r')
+        err = list(map(lambda x: x.strip(), err))
+        err = list(filter(None, err))
+        expected = u'Output tensor: [4/5]  80%|████████  , {} [00:00<00:00]'.format(out_msg)
+        assert err[-1] == expected
+
+    _test(out_tensor=torch.tensor([5, 0]), out_msg="output_0=5, output_1=0")
+    _test(out_tensor=torch.tensor(123), out_msg="output=123")
+    _test(out_tensor=torch.tensor(1.234), out_msg="output=1.23")
 
 
 def test_pbar_output_warning(capsys):
     loader = [1, 2, 3, 4, 5]
 
     def update_fn(engine, batch):
-        return batch, "abc"
+        return torch.zeros(1, 2, 3, 4)
 
     engine = Engine(update_fn)
 

pip install -e .
parse_log_pytest
pytest
numpy mock pytest codecov pytest-cov matplotlib pandas gym tqdm scikit-learn tensorboardX visdom polyaxon-client mlflow
apt-get update apt-get install -y gcc
3.6
pytest --no-header -rA --tb=line --color=no -p no:cacheprovider -W ignore::DeprecationWarning
alembic==1.7.7
attrs @ file:///opt/conda/conda-bld/attrs_1642510447205/work
certifi==2021.5.30
charset-normalizer==2.0.12
click==7.1.2
cloudpickle==2.2.1
codecov==2.1.13
coverage==6.2
cycler==0.11.0
databricks-cli==0.17.8
dataclasses==0.8
decorator==4.4.2
docker==5.0.3
entrypoints==0.4
Flask==1.1.4
gitdb==4.0.9
GitPython==3.1.18
greenlet==2.0.2
gunicorn==21.2.0
gym==0.26.2
gym-notices==0.0.8
hestia==0.6.0
idna==3.10
importlib-metadata @ file:///tmp/build/80754af9/importlib-metadata_1631916693255/work
importlib-resources==5.4.0
iniconfig @ file:///home/linux1/recipes/ci/iniconfig_1610983019677/work
itsdangerous==1.1.0
Jinja2==2.10.3
joblib==1.1.1
jsonpatch==1.32
jsonpointer==2.3
kiwisolver==1.3.1
Mako==1.1.6
MarkupSafe==2.0.1
marshmallow==3.0.0rc5
matplotlib==3.3.4
mlflow==1.23.1
mock==5.2.0
more-itertools @ file:///tmp/build/80754af9/more-itertools_1637733554872/work
networkx==2.5.1
numpy==1.19.5
oauthlib==3.2.2
packaging @ file:///tmp/build/80754af9/packaging_1637314298585/work
pandas==1.1.5
Pillow==8.4.0
pluggy @ file:///tmp/build/80754af9/pluggy_1615976315926/work
polyaxon-client==0.6.1
polyaxon-schemas==0.6.1
polystores==0.2.5
prometheus-client==0.17.1
prometheus_flask_exporter==0.23.2
protobuf==4.21.0
psutil==7.0.0
py @ file:///opt/conda/conda-bld/py_1644396412707/work
PyJWT==2.4.0
pyparsing @ file:///tmp/build/80754af9/pyparsing_1635766073266/work
pytest==6.2.4
pytest-cov==4.0.0
python-dateutil==2.9.0.post0
-e git+https://github.com/pytorch/ignite.git@10f18a224925caba95dbc119b38cb252a5a3481d#egg=pytorch_ignite
pytz==2025.2
PyYAML==6.0.1
querystring-parser==1.2.4
requests==2.27.1
requests-toolbelt==1.0.0
rhea==0.5.5
scikit-learn==0.24.2
scipy==1.5.4
six==1.17.0
smmap==5.0.0
SQLAlchemy==1.4.54
sqlparse==0.4.4
tabulate==0.8.10
tensorboardX==2.6.2.2
threadpoolctl==3.1.0
toml @ file:///tmp/build/80754af9/toml_1616166611790/work
tomli==1.2.3
torch==1.10.2
tornado==6.1
tqdm==4.64.1
typing_extensions @ file:///opt/conda/conda-bld/typing_extensions_1647553014482/work
urllib3==1.26.20
visdom==0.2.4
websocket-client==1.3.1
Werkzeug==1.0.1
zipp @ file:///tmp/build/80754af9/zipp_1633618647012/work

name: ignite
channels:
  - defaults
  - https://repo.anaconda.com/pkgs/main
  - https://repo.anaconda.com/pkgs/r
  - conda-forge
dependencies:
  - _libgcc_mutex=0.1=main
  - _openmp_mutex=5.1=1_gnu
  - attrs=21.4.0=pyhd3eb1b0_0
  - ca-certificates=2025.2.25=h06a4308_0
  - certifi=2021.5.30=py36h06a4308_0
  - importlib-metadata=4.8.1=py36h06a4308_0
  - importlib_metadata=4.8.1=hd3eb1b0_0
  - iniconfig=1.1.1=pyhd3eb1b0_0
  - ld_impl_linux-64=2.40=h12ee557_0
  - libffi=3.3=he6710b0_2
  - libgcc-ng=11.2.0=h1234567_1
  - libgomp=11.2.0=h1234567_1
  - libstdcxx-ng=11.2.0=h1234567_1
  - more-itertools=8.12.0=pyhd3eb1b0_0
  - ncurses=6.4=h6a678d5_0
  - openssl=1.1.1w=h7f8727e_0
  - packaging=21.3=pyhd3eb1b0_0
  - pip=21.2.2=py36h06a4308_0
  - pluggy=0.13.1=py36h06a4308_0
  - py=1.11.0=pyhd3eb1b0_0
  - pyparsing=3.0.4=pyhd3eb1b0_0
  - pytest=6.2.4=py36h06a4308_2
  - python=3.6.13=h12debd9_1
  - readline=8.2=h5eee18b_0
  - setuptools=58.0.4=py36h06a4308_0
  - sqlite=3.45.3=h5eee18b_0
  - tk=8.6.14=h39e8969_0
  - toml=0.10.2=pyhd3eb1b0_0
  - typing_extensions=4.1.1=pyh06a4308_0
  - wheel=0.37.1=pyhd3eb1b0_0
  - xz=5.6.4=h5eee18b_1
  - zipp=3.6.0=pyhd3eb1b0_0
  - zlib=1.2.13=h5eee18b_1
  - pip:
      - alembic==1.7.7
      - charset-normalizer==2.0.12
      - click==7.1.2
      - cloudpickle==2.2.1
      - codecov==2.1.13
      - coverage==6.2
      - cycler==0.11.0
      - databricks-cli==0.17.8
      - dataclasses==0.8
      - decorator==4.4.2
      - docker==5.0.3
      - entrypoints==0.4
      - flask==1.1.4
      - gitdb==4.0.9
      - gitpython==3.1.18
      - greenlet==2.0.2
      - gunicorn==21.2.0
      - gym==0.26.2
      - gym-notices==0.0.8
      - hestia==0.6.0
      - idna==3.10
      - importlib-resources==5.4.0
      - itsdangerous==1.1.0
      - jinja2==2.10.3
      - joblib==1.1.1
      - jsonpatch==1.32
      - jsonpointer==2.3
      - kiwisolver==1.3.1
      - mako==1.1.6
      - markupsafe==2.0.1
      - marshmallow==3.0.0rc5
      - matplotlib==3.3.4
      - mlflow==1.23.1
      - mock==5.2.0
      - networkx==2.5.1
      - numpy==1.19.5
      - oauthlib==3.2.2
      - pandas==1.1.5
      - pillow==8.4.0
      - polyaxon-client==0.6.1
      - polyaxon-schemas==0.6.1
      - polystores==0.2.5
      - prometheus-client==0.17.1
      - prometheus-flask-exporter==0.23.2
      - protobuf==4.21.0
      - psutil==7.0.0
      - pyjwt==2.4.0
      - pytest-cov==4.0.0
      - python-dateutil==2.9.0.post0
      - pytz==2025.2
      - pyyaml==6.0.1
      - querystring-parser==1.2.4
      - requests==2.27.1
      - requests-toolbelt==1.0.0
      - rhea==0.5.5
      - scikit-learn==0.24.2
      - scipy==1.5.4
      - six==1.17.0
      - smmap==5.0.0
      - sqlalchemy==1.4.54
      - sqlparse==0.4.4
      - tabulate==0.8.10
      - tensorboardx==2.6.2.2
      - threadpoolctl==3.1.0
      - tomli==1.2.3
      - torch==1.10.2
      - tornado==6.1
      - tqdm==4.64.1
      - urllib3==1.26.20
      - visdom==0.2.4
      - websocket-client==1.3.1
      - werkzeug==1.0.1
prefix: /opt/conda/envs/ignite

tests/ignite/contrib/handlers/test_tqdm_logger.py::test_pbar tests/ignite/contrib/handlers/test_tqdm_logger.py::test_pbar_with_metric tests/ignite/contrib/handlers/test_tqdm_logger.py::test_pbar_with_all_metric tests/ignite/contrib/handlers/test_tqdm_logger.py::test_pbar_with_output tests/ignite/contrib/handlers/test_tqdm_logger.py::test_pbar_with_scalar_output tests/ignite/contrib/handlers/test_tqdm_logger.py::test_pbar_with_tqdm_kwargs tests/ignite/contrib/handlers/test_tqdm_logger.py::test_pbar_output_tensor
tests/ignite/contrib/handlers/test_tqdm_logger.py::test_pbar_log_message tests/ignite/contrib/handlers/test_tqdm_logger.py::test_attach_fail_with_string tests/ignite/contrib/handlers/test_tqdm_logger.py::test_pbar_no_metric_names tests/ignite/contrib/handlers/test_tqdm_logger.py::test_pbar_fail_with_non_callable_transform tests/ignite/contrib/handlers/test_tqdm_logger.py::test_pbar_with_str_output tests/ignite/contrib/handlers/test_tqdm_logger.py::test_pbar_for_validation tests/ignite/contrib/handlers/test_tqdm_logger.py::test_pbar_output_warning tests/ignite/contrib/handlers/test_tqdm_logger.py::test_pbar_on_epochs tests/ignite/contrib/handlers/test_tqdm_logger.py::test_pbar_wrong_events_order tests/ignite/contrib/handlers/test_tqdm_logger.py::test_pbar_on_custom_events tests/ignite/contrib/handlers/test_tqdm_logger.py::test_pbar_with_nan_input
ignite/contrib/handlers/tqdm_logger.py
ignite/contrib/handlers/tqdm_logger.py