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Concepts·Certified Associate Python Programmer

Python File Streams, Modes and Handles

PCAP objective 5.4 is understand basic input/output terminology, and it is the vocabulary objective for files: stream, handle, mode, text against binary. `open()` returns an object with a `name`, a `mode` and an `encoding`; the mode letter decides what you may do and whether the file is truncated; and five distinct things can go wrong, each with its own exception.

Files and Streams Guide 23 of 25 Intermediate

Written against the versions above. `open()` returns a `TextIOWrapper` in text mode in Python 3 and the `io` module is the machinery behind it. Python 2's `file` type no longer exists. The default encoding for `open()` is locale-dependent - UTF-8 on this machine - which is why passing `encoding=` explicitly is good practice.

One machine, and any shell with Python 3 will do - these exams test the language, not a distribution.
Server NameIP AddressOSRolesCPURAMHDD
RUNNER01192.168.0.27Ubuntu 26.04 LTSPython 3.14.4 - the only machine this path needs2 Core4 GB50 GB

Before you start

  1. What open returns

  2. The mode letters

  3. The five things that go wrong

  4. with closes the file whatever happens

  5. The three streams that are always open

  6. What the exam does with this objective

Official sources

← All PCAP guides