Python Pocket Reference, 3rd Edition

Specific Built-in Types

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is usually equivalent to a string method call such as:

res = X.replace('span', 'spam')

But the string method call form is preferred and quicker, and

string methods require no module imports. Note that the

string.join(list, delim) operation becomes a method of

the delimiter string

delim.join(list).

Unicode Strings

Python supports Unicode (wide) character strings, which

represent each character with 16 (or more) bits, not 8.

Literals

Unicode strings are written as u"string". Arbitrary Uni-

code characters can be written using a special escape

sequence,

\uHHHH, where HHHH is a four-digit hexadecimal

number from

0000 to FFFF. The traditional \xHH escape

sequence can also be used, and octal escapes can be used

for characters up to

+01FF, which is represented by \777.

Operations

Like normal strings, all immutable sequence operations

apply. Normal and Unicode string objects can be freely

mixed; combining 8-bit and Unicode strings always coerces

to Unicode, using the default ASCII encoding (e.g., the result

of

'a' + u'bc' is u'abc'). Mixed-type operations assume the

8-bit string contains 7-bit U.S. ASCII data (and raise an error

for non-ASCII characters). The built-in

str() and unicode()

functions can be used to convert between normal and Uni-

code strings. The

encode string method applies a desired

encoding scheme to Unicode strings. A handful of related

modules (e.g.,

codecs) and built-in