diff --git "a/data/3.python\351\253\230\351\230\266/2.\347\273\223\346\236\204\345\214\226\346\225\260\346\215\256\345\210\206\346\236\220\345\267\245\345\205\267Pandas/4.\351\253\230\347\272\247\345\272\224\347\224\250/stat.json" "b/data/3.python\351\253\230\351\230\266/2.\347\273\223\346\236\204\345\214\226\346\225\260\346\215\256\345\210\206\346\236\220\345\267\245\345\205\267Pandas/4.\351\253\230\347\272\247\345\272\224\347\224\250/stat.json"
index 2354915ff52965300feaae9c48b3d1759436a20e..237918b7879bef28f8f93b13fe8b5b2aabf6e0b4 100644
--- "a/data/3.python\351\253\230\351\230\266/2.\347\273\223\346\236\204\345\214\226\346\225\260\346\215\256\345\210\206\346\236\220\345\267\245\345\205\267Pandas/4.\351\253\230\347\272\247\345\272\224\347\224\250/stat.json"
+++ "b/data/3.python\351\253\230\351\230\266/2.\347\273\223\346\236\204\345\214\226\346\225\260\346\215\256\345\210\206\346\236\220\345\267\245\345\205\267Pandas/4.\351\253\230\347\272\247\345\272\224\347\224\250/stat.json"
@@ -1,6 +1,7 @@
 {
-  "source": "stat.py",
-  "depends": [],
-  "exercise_id": 125,
-  "type": "code_options"
+    "author": "huanhuilong",
+    "source": "stat.md",
+    "depends": [],
+    "exercise_id": 125,
+    "type": "code_options"
 }
\ No newline at end of file
diff --git "a/data/3.python\351\253\230\351\230\266/2.\347\273\223\346\236\204\345\214\226\346\225\260\346\215\256\345\210\206\346\236\220\345\267\245\345\205\267Pandas/4.\351\253\230\347\272\247\345\272\224\347\224\250/stat.md" "b/data/3.python\351\253\230\351\230\266/2.\347\273\223\346\236\204\345\214\226\346\225\260\346\215\256\345\210\206\346\236\220\345\267\245\345\205\267Pandas/4.\351\253\230\347\272\247\345\272\224\347\224\250/stat.md"
new file mode 100644
index 0000000000000000000000000000000000000000..95a4c8301856c326a24d6649f309b1e18e4416bd
--- /dev/null
+++ "b/data/3.python\351\253\230\351\230\266/2.\347\273\223\346\236\204\345\214\226\346\225\260\346\215\256\345\210\206\346\236\220\345\267\245\345\205\267Pandas/4.\351\253\230\347\272\247\345\272\224\347\224\250/stat.md"
@@ -0,0 +1,118 @@
+# pandas dataframe之apply
+
+apply的使用
+
+
+## template
+
+```python
+import pandas as pd
+import numpy as np
+
+def add_val(num):
+    if num > 0:
+        return 1
+    else:
+        return 0
+
+
+if __name__ == '__main__':
+    data = {
+        'cloumn_one': pd.Series(np.random.randint(-10, 10, size=5)),
+        'cloumn_two': pd.Series(np.random.randint(0, 10, size=5)),
+        'cloumn_three': pd.Series(np.random.randint(0, 10, size=5))
+    }
+    data_df = pd.DataFrame(data)
+
+    data_df['label_one'] = data['cloumn_one'].apply(add_val)
+
+    print(data_df)
+```
+
+## 答案
+
+```python
+import pandas as pd
+import numpy as np
+
+if __name__ == '__main__':
+    data = {
+        'cloumn_one': pd.Series(np.random.randint(-10, 10, size=5)),
+        'cloumn_two': pd.Series(np.random.randint(0, 10, size=5)),
+        'cloumn_three': pd.Series(np.random.randint(0, 10, size=5))
+    }
+    data_df = pd.DataFrame(data)
+
+    data_df['label_one'] = data['cloumn_one'].apply['num'>1]
+
+    print(data_df)
+```
+
+## 选项
+
+### A
+
+```python
+import pandas as pd
+import numpy as np
+
+def add_val(num):
+    if num > 0:
+        return 1
+    else:
+        return 0
+
+
+if __name__ == '__main__':
+    data = {
+        'cloumn_one': pd.Series(np.random.randint(-10, 10, size=5)),
+        'cloumn_two': pd.Series(np.random.randint(0, 10, size=5)),
+        'cloumn_three': pd.Series(np.random.randint(0, 10, size=5))
+    }
+    data_df = pd.DataFrame(data)
+
+    data_df['label_one'] = data['cloumn_one'].apply(add_val)
+
+    print(data_df)
+```
+
+### B
+
+```python
+import pandas as pd
+import numpy as np
+
+if __name__ == '__main__':
+    data = {
+        'cloumn_one': pd.Series(np.random.randint(-10, 10, size=5)),
+        'cloumn_two': pd.Series(np.random.randint(0, 10, size=5)),
+        'cloumn_three': pd.Series(np.random.randint(0, 10, size=5))
+    }
+    data_df = pd.DataFrame(data)
+
+    data_df['label_one'] = data['cloumn_one'].apply(lambda num: 1 if num>0 else 0)
+
+    print(data_df)
+```
+
+### C
+
+```python
+import pandas as pd
+import numpy as np
+
+if __name__ == '__main__':
+    data = {
+        'cloumn_one': pd.Series(np.random.randint(-10, 10, size=5)),
+        'cloumn_two': pd.Series(np.random.randint(0, 10, size=5)),
+        'cloumn_three': pd.Series(np.random.randint(0, 10, size=5))
+    }
+    data_df = pd.DataFrame(data)
+
+    def add_val(num):
+        return 1 if num>0 else 0
+
+    data_df['label_one'] = data['cloumn_one'].apply(add_val)
+
+    print(data_df)
+```