Python Koans是一个学习Python编程语言的交互式教程，通过解决当中的问题来更深刻地理解Python。本系列文章为在此项目的学习中的问题解决方案及思考

Lesson 2 String

字符串是 Python 中最常用的数据类型。我们可以使用引号’或”来创建字符串。

about_strings.py

#!/usr/bin/env python

# -*- coding: utf-8 -*-

from runner.koan import *

class AboutStrings(Koan):

def test_double_quoted_strings_are_strings(self):

string = "Hello, world."

self.assertEqual(True, isinstance(string, str))

def test_single_quoted_strings_are_also_strings(self):

string = 'Goodbye, world.'

self.assertEqual(True, isinstance(string, str))

def test_triple_quote_strings_are_also_strings(self):

string = """Howdy, world!"""

self.assertEqual(True, isinstance(string, str))

def test_triple_single_quotes_work_too(self):

string = '''Bonjour tout le monde!'''

self.assertEqual(True, isinstance(string, str))

def test_raw_strings_are_also_strings(self):

string = r"Konnichi wa, world!"

self.assertEqual(True, isinstance(string, str))

def test_use_single_quotes_to_create_string_with_double_quotes(self):

string = 'He said, "Go Away."'

self.assertEqual('He said, "Go Away."', string)

def test_use_double_quotes_to_create_strings_with_single_quotes(self):

string = "Don't"

self.assertEqual("Don't", string)

def test_use_backslash_for_escaping_quotes_in_strings(self):

a = "He said, "Don't""

b = 'He said, "Don't"'

self.assertEqual(True, (a == b))

def test_use_backslash_at_the_end_of_a_line_to_continue_onto_the_next_line(self):

string = "It was the best of times,n

It was the worst of times."

self.assertEqual(52, len(string))

def test_triple_quoted_strings_can_span_lines(self):

string = """

Howdy,

world!

"""

self.assertEqual(15, len(string))

def test_triple_quoted_strings_need_less_escaping(self):

a = "Hello "world"."

b = """Hello "world"."""

self.assertEqual(True, (a == b))

def test_escaping_quotes_at_the_end_of_triple_quoted_string(self):

string = """Hello "world""""

self.assertEqual("""Hello "world"""", string)

def test_plus_concatenates_strings(self):

string = "Hello, " + "world"

self.assertEqual("Hello, world", string)

def test_adjacent_strings_are_concatenated_automatically(self):

string = "Hello" ", " "world"

self.assertEqual("Hello, world", string)

def test_plus_will_not_modify_original_strings(self):

hi = "Hello, "

there = "world"

string = hi + there

self.assertEqual("Hello, ", hi)

self.assertEqual("world", there)

def test_plus_equals_will_append_to_end_of_string(self):

hi = "Hello, "

there = "world"

hi += there

self.assertEqual("Hello, world", hi)

def test_plus_equals_also_leaves_original_string_unmodified(self):

original = "Hello, "

hi = original

there = "world"

hi += there

self.assertEqual("Hello, ", original)

def test_most_strings_interpret_escape_characters(self):

string = "n"

self.assertEqual('n', string)

self.assertEqual("""n""", string)

self.assertEqual(1, len(string))