Streaming Output from Subprocess.communicate()
When using subprocess.communicate() to retrieve output from a process, the entirety of the standard output (stdout) may be returned at once, preventing real-time monitoring of the output. This issue arises because of the blocking nature of the communicate() function.
To address this, one can adopt a streaming approach to printing each line of stdout as it becomes available. This can be achieved by employing iterators and manipulating the bufsize parameter of Popen().
In Python 2:
from subprocess import Popen, PIPE p = Popen(["cmd", "arg1"], stdout=PIPE, bufsize=1) with p.stdout: for line in iter(p.stdout.readline, b''): print(line) p.wait()
In Python 3, the code becomes:
from subprocess import Popen, PIPE with Popen(["cmd", "arg1"], stdout=PIPE, bufsize=1, universal_newlines=True) as p: for line in p.stdout: print(line, end='')
The bufsize=1 parameter forces the process to flush its output buffer after each line, ensuring that each line is printed immediately. iter() allows lines to be read asynchronously, making it possible to stream the output. The process termination is handled with the wait() method.
By using this streaming approach, you can monitor the output of a long-running process in real time without compromising the synchronous nature of the communicate() function.
The above is the detailed content of How Can I Stream Subprocess Output in Real-Time Using Python?. For more information, please follow other related articles on the PHP Chinese website!

TomergelistsinPython,youcanusethe operator,extendmethod,listcomprehension,oritertools.chain,eachwithspecificadvantages:1)The operatorissimplebutlessefficientforlargelists;2)extendismemory-efficientbutmodifiestheoriginallist;3)listcomprehensionoffersf

In Python 3, two lists can be connected through a variety of methods: 1) Use operator, which is suitable for small lists, but is inefficient for large lists; 2) Use extend method, which is suitable for large lists, with high memory efficiency, but will modify the original list; 3) Use * operator, which is suitable for merging multiple lists, without modifying the original list; 4) Use itertools.chain, which is suitable for large data sets, with high memory efficiency.

Using the join() method is the most efficient way to connect strings from lists in Python. 1) Use the join() method to be efficient and easy to read. 2) The cycle uses operators inefficiently for large lists. 3) The combination of list comprehension and join() is suitable for scenarios that require conversion. 4) The reduce() method is suitable for other types of reductions, but is inefficient for string concatenation. The complete sentence ends.

PythonexecutionistheprocessoftransformingPythoncodeintoexecutableinstructions.1)Theinterpreterreadsthecode,convertingitintobytecode,whichthePythonVirtualMachine(PVM)executes.2)TheGlobalInterpreterLock(GIL)managesthreadexecution,potentiallylimitingmul

Key features of Python include: 1. The syntax is concise and easy to understand, suitable for beginners; 2. Dynamic type system, improving development speed; 3. Rich standard library, supporting multiple tasks; 4. Strong community and ecosystem, providing extensive support; 5. Interpretation, suitable for scripting and rapid prototyping; 6. Multi-paradigm support, suitable for various programming styles.

Python is an interpreted language, but it also includes the compilation process. 1) Python code is first compiled into bytecode. 2) Bytecode is interpreted and executed by Python virtual machine. 3) This hybrid mechanism makes Python both flexible and efficient, but not as fast as a fully compiled language.

Useaforloopwheniteratingoverasequenceorforaspecificnumberoftimes;useawhileloopwhencontinuinguntilaconditionismet.Forloopsareidealforknownsequences,whilewhileloopssuitsituationswithundeterminediterations.

Pythonloopscanleadtoerrorslikeinfiniteloops,modifyinglistsduringiteration,off-by-oneerrors,zero-indexingissues,andnestedloopinefficiencies.Toavoidthese:1)Use'i


Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Article

Hot Tools

SublimeText3 English version
Recommended: Win version, supports code prompts!

EditPlus Chinese cracked version
Small size, syntax highlighting, does not support code prompt function

VSCode Windows 64-bit Download
A free and powerful IDE editor launched by Microsoft

Dreamweaver Mac version
Visual web development tools

Atom editor mac version download
The most popular open source editor
