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Diffstat (limited to 'advanced_python/18_with_statement.ipyml')
| -rw-r--r-- | advanced_python/18_with_statement.ipyml | 39 |
1 files changed, 18 insertions, 21 deletions
diff --git a/advanced_python/18_with_statement.ipyml b/advanced_python/18_with_statement.ipyml index b231d39..57ccc38 100644 --- a/advanced_python/18_with_statement.ipyml +++ b/advanced_python/18_with_statement.ipyml @@ -2,7 +2,7 @@ cells: - markdown: | # Advanced Python: `with` statements - + ### Prabhu Ramachandran ### The FOSSEE Python group & ### Department of Aerospace Engineering @@ -14,7 +14,7 @@ cells: - markdown: | ## Introduction - + - `with` statement is used as follows metadata: @@ -26,19 +26,17 @@ cells: for line in f: print(line, end='') - id: 0 - code: | f.closed - id: 1 metadata: slideshow: slide_type: fragment - markdown: | ## Observations - + - Creates a context - `f` is automatically closed - Works even if there was an exception! @@ -49,7 +47,7 @@ cells: - markdown: | ## Use cases - + - Use it with locks (for threaded computing) - Database connections - File objects @@ -60,7 +58,7 @@ cells: - markdown: | ## Creating your own - + - Relatively easy to do metadata: @@ -69,7 +67,7 @@ cells: - code: | from contextlib import contextmanager - + @contextmanager def context(): print("setup") @@ -78,23 +76,23 @@ cells: finally: print("done") + - code: | with context(): print("do something") + - markdown: | ## A more complex example - metadata: slideshow: slide_type: slide - - code: | import os from contextlib import contextmanager - + @contextmanager def tempfile(filename): f = open(filename, 'w') @@ -104,6 +102,11 @@ cells: f.close() os.remove(filename) + +- code: | + %ls junk.txt + + - code: | with tempfile('junk.txt') as f: f.write('hello world\n') @@ -114,8 +117,8 @@ cells: slide_type: slide - markdown: | - ## Comments - + ## Summary + - Useful feature - Can define an object supporting this - Overload, `__enter__` and `__exit__` @@ -125,11 +128,9 @@ cells: slideshow: slide_type: slide - - - markdown: | ## More information - + - https://www.python.org/dev/peps/pep-0343 - [With statement](https://docs.python.org/3/reference/datamodel.html#with-statement-context-managers) - [Context manager types](https://docs.python.org/3/library/stdtypes.html#typecontextmanager) @@ -154,14 +155,10 @@ metadata: name: python nbconvert_exporter: python pygments_lexer: ipython3 - version: 3.6.0 + version: 3.5.2 rise: scroll: true transition: none nbformat: 4 nbformat_minor: 2 -# --------------------------------------------------------------------------- -data: - [{execution_count: null, outputs: []}, {execution_count: null, outputs: []}, {execution_count: null, - outputs: []}, {execution_count: null, outputs: []}, {execution_count: null, outputs: []}] |