example-of-LogReader.md

+```python
+from visualdl import LogWriter, LogReader
+import random
+
+def write(log_dir):
+    log_writer = LogWriter(dir = log_dir, sync_cycle = 5)
+    with log_writer.mode("train") as logw:
+        # this scalar will record value in mode "train" and has tag "record1"
+        scalar_train_1 = logw.scalar("record1")
+        # this scalar will record value in mode "train" and has tag "record2"
+        scalar_train_2 = logw.scalar("record2")
+        
+    with log_writer.mode("test") as logw:
+        # this scalar will record value in mode "test" and has tag "record1"
+        scalar_val_1 = logw.scalar("record1")
+        # this scalar will record value in mode "test" and has tag "record2"
+        scalar_val_2 = logw.scalar("record2")
+        
+    for i in range(5):
+        # add scalar record with step from 0 to 4
+        scalar_train_1.add_record(i, random.random())
+        scalar_train_2.add_record(i, random.random())
+        scalar_val_1.add_record(i, random.random())
+        scalar_val_2.add_record(i, random.random())
+
+def read(log_dir):
+    log_reader = LogReader(dir = log_dir)
+    
+    # get all mode
+    modes = log_reader.modes()
+    for mode in modes:
+        # switch log_reader to appointed mode
+        with log_reader.mode(mode) as logr:
+            # get all tags, in this case, tag will be record1 or record2
+            tags = logr.tags("scalar")
+            for tag in tags:
+                # each tag consists of many records
+                records = logr.scalar(tag = tag).records()
+                for step, record in enumerate(records):
+                    print("mode %s -- tag %s -- step %d -- val %.2f" % (mode, tag, step, record))
+        
+if __name__ == "__main__":
+    log_dir = "vdl_log"
+    write(log_dir)
+    read(log_dir)
+```
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