From c95e741efff6429383d9a24e6583a0563debcfa5 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Jure=20=C5=A0orn?= Date: Mon, 22 Jan 2024 00:54:58 +0100 Subject: [PATCH] Print, Input, Command line arguments --- README.md | 25 ++++++++++++------------- index.html | 30 +++++++++++++++--------------- 2 files changed, 27 insertions(+), 28 deletions(-) diff --git a/README.md b/README.md index 8e9d64b..6b516af 100644 --- a/README.md +++ b/README.md @@ -1509,24 +1509,23 @@ Print print(, ..., sep=' ', end='\n', file=sys.stdout, flush=False) ``` * **Use `'file=sys.stderr'` for messages about errors.** -* **Use `'flush=True'` to forcibly flush the stream.** +* **Stdout and stderr streams hold output in a buffer until they receive a string containing '\n' or '\r', buffer reaches 4096 characters, `'flush=True'` is used, or program exits.** ### Pretty Print ```python from pprint import pprint pprint(, width=80, depth=None, compact=False, sort_dicts=True) ``` -* **Levels deeper than 'depth' get replaced by '...'.** +* **Each item is printed on its own line if collection takes up more than 'width' characters.** +* **Nested collections that are 'depth' levels deep get printed as '...'.** Input ----- -**Reads a line from the user input or pipe if present.** - ```python = input(prompt=None) ``` -* **Trailing newline gets stripped.** +* **Reads a line from the user input or pipe if present (trailing newline gets stripped).** * **Prompt string is printed to the standard output before reading input.** * **Raises EOFError when user hits EOF (ctrl-d/ctrl-z⏎) or input stream gets exhausted.** @@ -1542,18 +1541,18 @@ arguments = sys.argv[1:] ### Argument Parser ```python from argparse import ArgumentParser, FileType -p = ArgumentParser(description=) -p.add_argument('-', '--', action='store_true') # Flag. -p.add_argument('-', '--', type=) # Option. -p.add_argument('', type=, nargs=1) # First argument. -p.add_argument('', type=, nargs='+') # Remaining arguments. +p = ArgumentParser(description=) # Returns a parser. +p.add_argument('-', '--', action='store_true') # Flag (defaults to False). +p.add_argument('-', '--', type=) # Option (defaults to None). +p.add_argument('', type=, nargs=1) # Mandatory first argument. +p.add_argument('', type=, nargs='+') # Mandatory remaining args. p.add_argument('', type=, nargs='*') # Optional arguments. -args = p.parse_args() # Exits on error. -value = args. + = p.parse_args() # Exits on parsing error. + = . # Returns `()`. ``` * **Use `'help='` to set argument description that will be displayed in help message.** -* **Use `'default='` to set argument's default value.** +* **Use `'default='` to set option's default value.** * **Use `'type=FileType()'` for files. Accepts 'encoding', but 'newline' is None.** diff --git a/index.html b/index.html index e7add9d..285d183 100644 --- a/index.html +++ b/index.html @@ -54,7 +54,7 @@
- +
@@ -1282,21 +1282,21 @@ sys.exit(<int>) # Exits with
  • Use 'file=sys.stderr' for messages about errors.
    • -
  • Use 'flush=True' to forcibly flush the stream.
    • +
  • Stdout and stderr streams hold output in a buffer until they receive a string containing '\n' or '\r', buffer reaches 4096 characters, 'flush=True' is used, or program exits.

Pretty Print

from pprint import pprint
 pprint(<collection>, width=80, depth=None, compact=False, sort_dicts=True)
    -
  • Levels deeper than 'depth' get replaced by '…'.
    • +
  • Each item is printed on its own line if collection takes up more than 'width' characters.
    • +
  • Nested collections that are 'depth' levels deep get printed as '…'.
-

#Input

Reads a line from the user input or pipe if present.

<str> = input(prompt=None)
+
#Input
<str> = input(prompt=None)
 

 
-
 
    
-
  • Trailing newline gets stripped.
    • 
+
  • Reads a line from the user input or pipe if present (trailing newline gets stripped).
    • 
 
  • Prompt string is printed to the standard output before reading input.
    • 
 
  • Raises EOFError when user hits EOF (ctrl-d/ctrl-z⏎) or input stream gets exhausted.
    • 
 

@@ -1306,19 +1306,19 @@ arguments    = sys.argv[1:]

Argument Parser

from argparse import ArgumentParser, FileType
-p = ArgumentParser(description=<str>)
-p.add_argument('-<short_name>', '--<name>', action='store_true')  # Flag.
-p.add_argument('-<short_name>', '--<name>', type=<type>)          # Option.
-p.add_argument('<name>', type=<type>, nargs=1)                    # First argument.
-p.add_argument('<name>', type=<type>, nargs='+')                  # Remaining arguments.
+p = ArgumentParser(description=<str>)                             # Returns a parser.
+p.add_argument('-<short_name>', '--<name>', action='store_true')  # Flag (defaults to False).
+p.add_argument('-<short_name>', '--<name>', type=<type>)          # Option (defaults to None).
+p.add_argument('<name>', type=<type>, nargs=1)                    # Mandatory first argument.
+p.add_argument('<name>', type=<type>, nargs='+')                  # Mandatory remaining args.
 p.add_argument('<name>', type=<type>, nargs='*')                  # Optional arguments.
-args  = p.parse_args()                                            # Exits on error.
-value = args.<name>
+<args> = p.parse_args()                                           # Exits on parsing error.
+<obj>  = <args>.<name>                                            # Returns `<type>(<arg>)`.
  • Use 'help=<str>' to set argument description that will be displayed in help message.
    • -
  • Use 'default=<el>' to set argument's default value.
    • +
  • Use 'default=<el>' to set option's default value.
  • Use 'type=FileType(<mode>)' for files. Accepts 'encoding', but 'newline' is None.

#Open

Opens the file and returns a corresponding file object.

<file> = open(<path>, mode='r', encoding=None, newline=None)
@@ -2932,7 +2932,7 @@ $ deactivate                  # Deactivates the activ