SoFunction
Updated on 2025-04-24

Summary of the usage of getopt module in Python

Introduction to getopt module

getoptModule is a module in Python that parses command line options and parameters

It provides a simple and flexible way to handle command line input

Introduction to functions

First, let’s introduce the usage of the function getop in the getopt module:

()Functions are standard library functions in Python for parsing command line parameters. This function extracts options and parameters from the command line and processes them.

The function signature is as follows:

(args, short_options, long_options=[])

Parameter description:

  • args: The command line parameter list to parse, usually starting from the first parameter (excluding script name)
  • short_options: A string containing all short options. Each option can be followed by a colon (:) to indicate that the option requires a value.
  • long_options: A list of all long options, each of which is expressed in a string. If an option requires a value, you can use an equal sign (=) to separate the options and values.

Return value:

()The function returns a tuple containing two lists:

  • args: A list of tuples containing parsed options and parameters. The first element of each tuple is an option (a short horizontal line is added before the short option, two short horizontal lines are added before the long option), and the second element is the value of the option (if any)
  • values: A list of unresolved positional parameters

For example:

import getopt
import sys
# Define short and long optionsshort_options = "ho:v"
long_options = ["help", "output=", "verbose"]
# parse command line parametersargs, values = ([1:], short_options, long_options)
# traversal analysis resultsfor opt, arg in args:
    if opt in ("-h", "--help"):
        print("Show Help Information")
    elif opt in ("-o", "--output"):
        print("Output file path:", arg)
    elif opt == "-v":
        print("Enable detailed output")

Short options are defined in the example above-h、-oand-v, and long options--help、--outputand--verbose, and then use()The function parses the command line parameters and traverses the parsing results for corresponding processing

in,Yes A list of command line parameters,[0]Represents the name of the script itself, and[1:]Represents all command line parameters starting from the first parameter

Common usage of getopt module

The following isgetoptSome common usage examples of modules:

Example 1: Basic usage

import getopt
import sys
# Define command line parameter listshort_options = "ho:v"
long_options = ["help", "output=", "verbose"]
# parse command line parametersargs, values = ([1:], short_options, long_options)
# Process the parsing resultsfor arg, value in args:
    if arg in ("-h", "--help"):
        print("Help Information")
    elif arg in ("-o", "--output"):
        output_file = value
        print("Output File:", output_file)
    elif arg == "-v":
        verbose = True
        print("Enable Detailed Mode")

Example 2: Handling position parameters

import getopt
import sys
# parse command line parametersargs, values = ([1:], "")
# Process the parsing resultsfor value in values:
    print("Position Parameters:", value)

Example 3: Handle options with parameter values

import getopt
import sys
# Define command line parameter listshort_options = "f:"
long_options = ["file="]
# parse command line parametersargs, values = ([1:], short_options, long_options)
# Process the parsing resultsfor arg, value in args:
    if arg in ("-f", "--file"):
        input_file = value
        print("Input File:", input_file)

Example 4: Error handling

import getopt
import sys
try:
    # parse command line parameters    args, values = ([1:], "ho:", ["help", "output="])
except  as err:
    print(str(err))  # Print error message    (2)
# Process the parsing resultsfor arg, value in args:
    if arg in ("-h", "--help"):
        print("Help Information")
    elif arg in ("-o", "--output"):
        output_file = value
        print("Output File:", output_file)

The above isgetoptSome common uses of modules include parsing command line options, handling positional parameters, handling options with parameter values, and error handling

Depending on specific needs, these usages can be combined with flexible command line parameter analysis

Replenish:

It's a PythonBuilt-in list, which contains the values ​​of command line parameters

in,[0]Represents the name of the script itself, and[1:]It means all command line parameters starting from the first parameter

Specifically, suppose that the following command is run in the terminal:

python  arg1 arg2 arg3

In this example,[0]Will be ,and[1:]Will be a included arg1、arg2 and arg3List of

By using[1:], you can get the parameter list passed to the script from the command line and process them in the program. This is very useful in handling command line tools, script parameter passing and other scenarios

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