[Term Entry] Python time-module: .mktime()

content/python/concepts/time-module/terms/mktime/mktime.md

@@ -0,0 +1,87 @@
+---
+Title: '.mktime()'
+Description: 'Converts a local time tuple or struct_time to seconds since the epoch.'
+Subjects:
+  - 'Code Foundations'
+  - 'Computer Science'
+  - 'Data Science'
+Tags:
+  - 'Time'
+  - 'Epoch'
+  - 'Python'
+CatalogContent:
+  - 'learn-python-3'
+  - 'paths/computer-science'
+---
+
+In the `time` module, the **`.mktime()`** function takes a `struct_time` object or a 9-element [tuple](https://www.codecademy.com/resources/docs/python/tuples) representing local time and returns a floating-point number of seconds since the [epoch](https://www.codecademy.com/resources/docs/general/machine-learning/epochs) (i.e., “Unix timestamp” in local time). It is effectively the inverse of `time.localtime()`.
+
+## Syntax
+
+```pseudo
+time.mktime(t)
+```
+
+**Parameters:**
+
+- `t`: A `time.struct_time` object or a full 9-element tuple (`(year, month, day, hour, minute, second, weekday, day_of_year, isdst)`) representing local time.
+
+**Return value:**
+
+A `float` representing seconds since the epoch in local time. Raises OverflowError or ValueError if the input cannot be represented.
+
+## Example 1: Basic conversion from tuple to timestamp
+
+This example converts a local time tuple directly into seconds since epoch:
+
+```py
+import time
+
+time_tuple = (2025, 4, 11, 14, 30, 0, 0, 0, -1)  # year, month, day, hour, minute, second, weekday, yearday, isdst
+timestamp = time.mktime(time_tuple)
+print("Timestamp:", timestamp)
+```
+
+The output of this code can be:
+
+```shell
+Timestamp: 1744381800.0
+```
+
+## Example 2: Convert current local time (via struct_time) to timestamp
+
+This example gets the current local time in `struct_time` form and then uses `.mktime()` to convert it to an epoch seconds value:
+
+```py
+import time
+
+local_struct = time.localtime()
+timestamp = time.mktime(local_struct)
+print("Current local seconds since epoch:", timestamp)
+```
+
+A possible output of this code is:
+
+```shell
+Current local seconds since epoch: 1762169287.0
+```
+
+## Codebyte Example
+
+This interactive example shows conversion and round-trip (timestamp ↔ struct_time) behaviour:
+
+```codebyte/python
+import time
+
+# Define a specific local time
+tup = (2023, 12, 31, 23, 59, 59, 0, 365, 0)
+ts = time.mktime(tup)
+print("Timestamp from tuple:", ts)
+
+# Convert timestamp back to struct_time (local time)
+struct_back = time.localtime(ts)
+print("Converted back to local time:", struct_back)
+
+# Show that mktime(localtime(ts)) returns ~ts
+print("Round-trip check:", time.mktime(struct_back))
+```

documentation/tags.md

@@ -132,6 +132,7 @@ Encapsulation
 Encoding
 Enum
 Environment Variables
+Epoch
 Equality
 Error Handling
 Errors