/usr/share/doc/python2-docs/html/_sources/library
NameSizeModeActions
2to3.rst.txt146470644editdlrm
abc.rst.txt72190644editdlrm
aepack.rst.txt42570644editdlrm
aetools.rst.txt35320644editdlrm
aetypes.rst.txt42570644editdlrm
aifc.rst.txt70860644editdlrm
al.rst.txt53090644editdlrm
allos.rst.txt6950644editdlrm
anydbm.rst.txt41110644editdlrm
archiving.rst.txt4240644editdlrm
argparse.rst.txt746850644editdlrm
array.rst.txt105240644editdlrm
ast.rst.txt101110644editdlrm
asynchat.rst.txt92060644editdlrm
asyncore.rst.txt129370644editdlrm
atexit.rst.txt39100644editdlrm
audioop.rst.txt103950644editdlrm
autogil.rst.txt10150644editdlrm
base64.rst.txt62520644editdlrm
basehttpserver.rst.txt104040644editdlrm
bastion.rst.txt26110644editdlrm
bdb.rst.txt124560644editdlrm
binascii.rst.txt65080644editdlrm
binhex.rst.txt19100644editdlrm
bisect.rst.txt54150644editdlrm
bsddb.rst.txt75750644editdlrm
bz2.rst.txt80640644editdlrm
calendar.rst.txt112820644editdlrm
carbon.rst.txt159560644editdlrm
cd.rst.txt119740644editdlrm
cgi.rst.txt228530644editdlrm
cgihttpserver.rst.txt27880644editdlrm
cgitb.rst.txt28740644editdlrm
chunk.rst.txt49550644editdlrm
cmath.rst.txt76470644editdlrm
cmd.rst.txt85650644editdlrm
code.rst.txt71150644editdlrm
codecs.rst.txt669660644editdlrm
codeop.rst.txt37740644editdlrm
collections.rst.txt414480644editdlrm
colorpicker.rst.txt9130644editdlrm
colorsys.rst.txt18190644editdlrm
commands.rst.txt25950644editdlrm
compileall.rst.txt46780644editdlrm
compiler.rst.txt374640644editdlrm
configparser.rst.txt196070644editdlrm
constants.rst.txt23280644editdlrm
contextlib.rst.txt60120644editdlrm
cookie.rst.txt95430644editdlrm
cookielib.rst.txt278750644editdlrm
copy.rst.txt33510644editdlrm
copy_reg.rst.txt23290644editdlrm
crypt.rst.txt22920644editdlrm
crypto.rst.txt3550644editdlrm
csv.rst.txt227570644editdlrm
ctypes.rst.txt905130644editdlrm
curses.ascii.rst.txt90460644editdlrm
curses.panel.rst.txt27400644editdlrm
curses.rst.txt748770644editdlrm
custominterp.rst.txt5700644editdlrm
datatypes.rst.txt8640644editdlrm
datetime.rst.txt746790644editdlrm
dbhash.rst.txt38650644editdlrm
dbm.rst.txt31170644editdlrm
debug.rst.txt4460644editdlrm
decimal.rst.txt709260644editdlrm
development.rst.txt6400644editdlrm
difflib.rst.txt307160644editdlrm
dircache.rst.txt18130644editdlrm
dis.rst.txt232480644editdlrm
distribution.rst.txt4260644editdlrm
distutils.rst.txt19580644editdlrm
dl.rst.txt33920644editdlrm
doctest.rst.txt739850644editdlrm
docxmlrpcserver.rst.txt38020644editdlrm
dumbdbm.rst.txt28410644editdlrm
dummy_thread.rst.txt10580644editdlrm
dummy_threading.rst.txt7990644editdlrm
easydialogs.rst.txt103460644editdlrm
email-examples.rst.txt12710644editdlrm
email.charset.rst.txt96540644editdlrm
email.encoders.rst.txt23760644editdlrm
email.errors.rst.txt40060644editdlrm
email.generator.rst.txt61320644editdlrm
email.header.rst.txt75310644editdlrm
email.iterators.rst.txt24210644editdlrm
email.message.rst.txt252170644editdlrm
email.mime.rst.txt99170644editdlrm
email.parser.rst.txt103270644editdlrm
email.rst.txt161110644editdlrm
email.utils.rst.txt64750644editdlrm
ensurepip.rst.txt50220644editdlrm
errno.rst.txt67080644editdlrm
exceptions.rst.txt183430644editdlrm
fcntl.rst.txt73610644editdlrm
filecmp.rst.txt53480644editdlrm
fileformats.rst.txt3020644editdlrm
fileinput.rst.txt74170644editdlrm
filesys.rst.txt8060644editdlrm
fl.rst.txt176460644editdlrm
fm.rst.txt26990644editdlrm
fnmatch.rst.txt31040644editdlrm
formatter.rst.txt132450644editdlrm
fpectl.rst.txt41710644editdlrm
fpformat.rst.txt17470644editdlrm
fractions.rst.txt52970644editdlrm
framework.rst.txt114440644editdlrm
frameworks.rst.txt3780644editdlrm
ftplib.rst.txt157200644editdlrm
functions.rst.txt755540644editdlrm
functools.rst.txt74480644editdlrm
future_builtins.rst.txt20100644editdlrm
gc.rst.txt90140644editdlrm
gdbm.rst.txt48820644editdlrm
gensuitemodule.rst.txt31130644editdlrm
getopt.rst.txt66700644editdlrm
getpass.rst.txt18760644editdlrm
gettext.rst.txt290400644editdlrm
gl.rst.txt60090644editdlrm
glob.rst.txt24140644editdlrm
grp.rst.txt22560644editdlrm
gzip.rst.txt48280644editdlrm
hashlib.rst.txt73790644editdlrm
heapq.rst.txt131850644editdlrm
hmac.rst.txt30730644editdlrm
hotshot.rst.txt42890644editdlrm
htmllib.rst.txt73790644editdlrm
htmlparser.rst.txt116400644editdlrm
httplib.rst.txt374540644editdlrm
i18n.rst.txt4090644editdlrm
ic.rst.txt50050644editdlrm
idle.rst.txt221820644editdlrm
imageop.rst.txt40010644editdlrm
imaplib.rst.txt172210644editdlrm
imgfile.rst.txt27650644editdlrm
imghdr.rst.txt26350644editdlrm
imp.rst.txt125930644editdlrm
importlib.rst.txt11260644editdlrm
imputil.rst.txt70230644editdlrm
index.rst.txt22870644editdlrm
inspect.rst.txt281510644editdlrm
internet.rst.txt9500644editdlrm
intro.rst.txt28030644editdlrm
io.rst.txt390150644editdlrm
ipc.rst.txt6300644editdlrm
itertools.rst.txt363240644editdlrm
jpeg.rst.txt38580644editdlrm
json.rst.txt255450644editdlrm
keyword.rst.txt6170644editdlrm
language.rst.txt5230644editdlrm
linecache.rst.txt18870644editdlrm
locale.rst.txt249750644editdlrm
logging.config.rst.txt315600644editdlrm
logging.handlers.rst.txt281530644editdlrm
logging.rst.txt468820644editdlrm
mac.rst.txt7910644editdlrm
macos.rst.txt38240644editdlrm
macosa.rst.txt39640644editdlrm
macostools.rst.txt40170644editdlrm
macpath.rst.txt6500644editdlrm
mailbox.rst.txt681290644editdlrm
mailcap.rst.txt36750644editdlrm
markup.rst.txt12490644editdlrm
marshal.rst.txt56890644editdlrm
math.rst.txt109200644editdlrm
md5.rst.txt28150644editdlrm
mhlib.rst.txt39660644editdlrm
mimetools.rst.txt45040644editdlrm
mimetypes.rst.txt98390644editdlrm
mimewriter.rst.txt33600644editdlrm
mimify.rst.txt35190644editdlrm
miniaeframe.rst.txt25640644editdlrm
misc.rst.txt2480644editdlrm
mm.rst.txt4470644editdlrm
mmap.rst.txt104810644editdlrm
modulefinder.rst.txt33800644editdlrm
modules.rst.txt3820644editdlrm
msilib.rst.txt190620644editdlrm
msvcrt.rst.txt43460644editdlrm
multifile.rst.txt66130644editdlrm
multiprocessing.rst.txt926210644editdlrm
mutex.rst.txt19390644editdlrm
netdata.rst.txt4320644editdlrm
netrc.rst.txt31190644editdlrm
new.rst.txt26530644editdlrm
nis.rst.txt21080644editdlrm
nntplib.rst.txt145310644editdlrm
numbers.rst.txt80070644editdlrm
numeric.rst.txt7510644editdlrm
operator.rst.txt220920644editdlrm
optparse.rst.txt771010644editdlrm
os.path.rst.txt130940644editdlrm
os.rst.txt825800644editdlrm
ossaudiodev.rst.txt173090644editdlrm
othergui.rst.txt27210644editdlrm
parser.rst.txt153850644editdlrm
pdb.rst.txt160430644editdlrm
persistence.rst.txt8260644editdlrm
pickle.rst.txt372620644editdlrm
pickletools.rst.txt19970644editdlrm
pipes.rst.txt37860644editdlrm
pkgutil.rst.txt77140644editdlrm
platform.rst.txt95540644editdlrm
plistlib.rst.txt41340644editdlrm
popen2.rst.txt70220644editdlrm
poplib.rst.txt62200644editdlrm
posix.rst.txt36300644editdlrm
posixfile.rst.txt72000644editdlrm
pprint.rst.txt90710644editdlrm
profile.rst.txt286660644editdlrm
pty.rst.txt17620644editdlrm
pwd.rst.txt27250644editdlrm
pyclbr.rst.txt32960644editdlrm
pydoc.rst.txt40830644editdlrm
pyexpat.rst.txt288910644editdlrm
python.rst.txt5140644editdlrm
py_compile.rst.txt24790644editdlrm
queue.rst.txt70340644editdlrm
quopri.rst.txt26700644editdlrm
random.rst.txt133190644editdlrm
re.rst.txt551020644editdlrm
readline.rst.txt105130644editdlrm
repr.rst.txt47180644editdlrm
resource.rst.txt95950644editdlrm
restricted.rst.txt33270644editdlrm
rexec.rst.txt117420644editdlrm
rfc822.rst.txt140370644editdlrm
rlcompleter.rst.txt24940644editdlrm
robotparser.rst.txt21900644editdlrm
runpy.rst.txt69380644editdlrm
sched.rst.txt46440644editdlrm
scrolledtext.rst.txt13790644editdlrm
select.rst.txt207050644editdlrm
sets.rst.txt149730644editdlrm
sgi.rst.txt3220644editdlrm
sgmllib.rst.txt106640644editdlrm
sha.rst.txt28070644editdlrm
shelve.rst.txt83190644editdlrm
shlex.rst.txt113130644editdlrm
shutil.rst.txt134910644editdlrm
signal.rst.txt107190644editdlrm
simplehttpserver.rst.txt45590644editdlrm
simplexmlrpcserver.rst.txt108810644editdlrm
site.rst.txt78800644editdlrm
smtpd.rst.txt24640644editdlrm
smtplib.rst.txt149060644editdlrm
sndhdr.rst.txt17590644editdlrm
socket.rst.txt407650644editdlrm
socketserver.rst.txt225120644editdlrm
someos.rst.txt5990644editdlrm
spwd.rst.txt28250644editdlrm
sqlite3.rst.txt354480644editdlrm
ssl.rst.txt765540644editdlrm
stat.rst.txt77780644editdlrm
statvfs.rst.txt13000644editdlrm
stdtypes.rst.txt1226680644editdlrm
string.rst.txt440850644editdlrm
stringio.rst.txt41660644editdlrm
stringprep.rst.txt42380644editdlrm
strings.rst.txt7460644editdlrm
struct.rst.txt171000644editdlrm
subprocess.rst.txt336480644editdlrm
sun.rst.txt2490644editdlrm
sunau.rst.txt71240644editdlrm
sunaudio.rst.txt58490644editdlrm
symbol.rst.txt9750644editdlrm
symtable.rst.txt50640644editdlrm
sys.rst.txt475200644editdlrm
sysconfig.rst.txt76390644editdlrm
syslog.rst.txt39310644editdlrm
tabnanny.rst.txt19990644editdlrm
tarfile.rst.txt282140644editdlrm
telnetlib.rst.txt74820644editdlrm
tempfile.rst.txt105040644editdlrm
termios.rst.txt37330644editdlrm
test.rst.txt176590644editdlrm
textwrap.rst.txt85520644editdlrm
thread.rst.txt65880644editdlrm
threading.rst.txt324680644editdlrm
time.rst.txt260200644editdlrm
timeit.rst.txt115980644editdlrm
tix.rst.txt226930644editdlrm
tk.rst.txt16120644editdlrm
tkinter.rst.txt334560644editdlrm
token.rst.txt24510644editdlrm
tokenize.rst.txt55700644editdlrm
trace.rst.txt67240644editdlrm
traceback.rst.txt107110644editdlrm
ttk.rst.txt574110644editdlrm
tty.rst.txt10110644editdlrm
turtle.rst.txt640970644editdlrm
types.rst.txt62000644editdlrm
undoc.rst.txt65500644editdlrm
unicodedata.rst.txt57360644editdlrm
unittest.rst.txt829520644editdlrm
unix.rst.txt4900644editdlrm
urllib.rst.txt249600644editdlrm
urllib2.rst.txt352110644editdlrm
urlparse.rst.txt160710644editdlrm
user.rst.txt27480644editdlrm
userdict.rst.txt92900644editdlrm
uu.rst.txt23690644editdlrm
uuid.rst.txt83780644editdlrm
warnings.rst.txt198150644editdlrm
wave.rst.txt50470644editdlrm
weakref.rst.txt129260644editdlrm
webbrowser.rst.txt98630644editdlrm
whichdb.rst.txt9310644editdlrm
windows.rst.txt2730644editdlrm
winsound.rst.txt50660644editdlrm
wsgiref.rst.txt305670644editdlrm
xdrlib.rst.txt80770644editdlrm
xml.dom.minidom.rst.txt112080644editdlrm
xml.dom.pulldom.rst.txt15710644editdlrm
xml.dom.rst.txt401820644editdlrm
xml.etree.elementtree.rst.txt357070644editdlrm
xml.rst.txt60900644editdlrm
xml.sax.handler.rst.txt153710644editdlrm
xml.sax.reader.rst.txt122570644editdlrm
xml.sax.rst.txt64600644editdlrm
xml.sax.utils.rst.txt35600644editdlrm
xmlrpclib.rst.txt225590644editdlrm
zipfile.rst.txt188710644editdlrm
zipimport.rst.txt59570644editdlrm
zlib.rst.txt127660644editdlrm
_winreg.rst.txt233050644editdlrm
__builtin__.rst.txt14940644editdlrm
__future__.rst.txt49520644editdlrm
__main__.rst.txt5350644editdlrm
Edit: /usr/share/doc/python2-docs/html/_sources/library/math.rst.txt (10920B)
:mod:`math` --- Mathematical functions ====================================== .. module:: math :synopsis: Mathematical functions (sin() etc.). .. testsetup:: from math import fsum This module is always available. It provides access to the mathematical functions defined by the C standard. These functions cannot be used with complex numbers; use the functions of the same name from the :mod:`cmath` module if you require support for complex numbers. The distinction between functions which support complex numbers and those which don't is made since most users do not want to learn quite as much mathematics as required to understand complex numbers. Receiving an exception instead of a complex result allows earlier detection of the unexpected complex number used as a parameter, so that the programmer can determine how and why it was generated in the first place. The following functions are provided by this module. Except when explicitly noted otherwise, all return values are floats. Number-theoretic and representation functions --------------------------------------------- .. function:: ceil(x) Return the ceiling of *x* as a float, the smallest integer value greater than or equal to *x*. .. function:: copysign(x, y) Return *x* with the sign of *y*. On a platform that supports signed zeros, ``copysign(1.0, -0.0)`` returns *-1.0*. .. versionadded:: 2.6 .. function:: fabs(x) Return the absolute value of *x*. .. function:: factorial(x) Return *x* factorial. Raises :exc:`ValueError` if *x* is not integral or is negative. .. versionadded:: 2.6 .. function:: floor(x) Return the floor of *x* as a float, the largest integer value less than or equal to *x*. .. function:: fmod(x, y) Return ``fmod(x, y)``, as defined by the platform C library. Note that the Python expression ``x % y`` may not return the same result. The intent of the C standard is that ``fmod(x, y)`` be exactly (mathematically; to infinite precision) equal to ``x - n*y`` for some integer *n* such that the result has the same sign as *x* and magnitude less than ``abs(y)``. Python's ``x % y`` returns a result with the sign of *y* instead, and may not be exactly computable for float arguments. For example, ``fmod(-1e-100, 1e100)`` is ``-1e-100``, but the result of Python's ``-1e-100 % 1e100`` is ``1e100-1e-100``, which cannot be represented exactly as a float, and rounds to the surprising ``1e100``. For this reason, function :func:`fmod` is generally preferred when working with floats, while Python's ``x % y`` is preferred when working with integers. .. function:: frexp(x) Return the mantissa and exponent of *x* as the pair ``(m, e)``. *m* is a float and *e* is an integer such that ``x == m * 2**e`` exactly. If *x* is zero, returns ``(0.0, 0)``, otherwise ``0.5 <= abs(m) < 1``. This is used to "pick apart" the internal representation of a float in a portable way. .. function:: fsum(iterable) Return an accurate floating point sum of values in the iterable. Avoids loss of precision by tracking multiple intermediate partial sums:: >>> sum([.1, .1, .1, .1, .1, .1, .1, .1, .1, .1]) 0.9999999999999999 >>> fsum([.1, .1, .1, .1, .1, .1, .1, .1, .1, .1]) 1.0 The algorithm's accuracy depends on IEEE-754 arithmetic guarantees and the typical case where the rounding mode is half-even. On some non-Windows builds, the underlying C library uses extended precision addition and may occasionally double-round an intermediate sum causing it to be off in its least significant bit. For further discussion and two alternative approaches, see the `ASPN cookbook recipes for accurate floating point summation `_\. .. versionadded:: 2.6 .. function:: isinf(x) Check if the float *x* is positive or negative infinity. .. versionadded:: 2.6 .. function:: isnan(x) Check if the float *x* is a NaN (not a number). For more information on NaNs, see the IEEE 754 standards. .. versionadded:: 2.6 .. function:: ldexp(x, i) Return ``x * (2**i)``. This is essentially the inverse of function :func:`frexp`. .. function:: modf(x) Return the fractional and integer parts of *x*. Both results carry the sign of *x* and are floats. .. function:: trunc(x) Return the :class:`~numbers.Real` value *x* truncated to an :class:`~numbers.Integral` (usually a long integer). Uses the ``__trunc__`` method. .. versionadded:: 2.6 Note that :func:`frexp` and :func:`modf` have a different call/return pattern than their C equivalents: they take a single argument and return a pair of values, rather than returning their second return value through an 'output parameter' (there is no such thing in Python). For the :func:`ceil`, :func:`floor`, and :func:`modf` functions, note that *all* floating-point numbers of sufficiently large magnitude are exact integers. Python floats typically carry no more than 53 bits of precision (the same as the platform C double type), in which case any float *x* with ``abs(x) >= 2**52`` necessarily has no fractional bits. Power and logarithmic functions ------------------------------- .. function:: exp(x) Return ``e**x``. .. function:: expm1(x) Return ``e**x - 1``. For small floats *x*, the subtraction in ``exp(x) - 1`` can result in a significant loss of precision; the :func:`expm1` function provides a way to compute this quantity to full precision:: >>> from math import exp, expm1 >>> exp(1e-5) - 1 # gives result accurate to 11 places 1.0000050000069649e-05 >>> expm1(1e-5) # result accurate to full precision 1.0000050000166668e-05 .. versionadded:: 2.7 .. function:: log(x[, base]) With one argument, return the natural logarithm of *x* (to base *e*). With two arguments, return the logarithm of *x* to the given *base*, calculated as ``log(x)/log(base)``. .. versionchanged:: 2.3 *base* argument added. .. function:: log1p(x) Return the natural logarithm of *1+x* (base *e*). The result is calculated in a way which is accurate for *x* near zero. .. versionadded:: 2.6 .. function:: log10(x) Return the base-10 logarithm of *x*. This is usually more accurate than ``log(x, 10)``. .. function:: pow(x, y) Return ``x`` raised to the power ``y``. Exceptional cases follow Annex 'F' of the C99 standard as far as possible. In particular, ``pow(1.0, x)`` and ``pow(x, 0.0)`` always return ``1.0``, even when ``x`` is a zero or a NaN. If both ``x`` and ``y`` are finite, ``x`` is negative, and ``y`` is not an integer then ``pow(x, y)`` is undefined, and raises :exc:`ValueError`. Unlike the built-in ``**`` operator, :func:`math.pow` converts both its arguments to type :class:`float`. Use ``**`` or the built-in :func:`pow` function for computing exact integer powers. .. versionchanged:: 2.6 The outcome of ``1**nan`` and ``nan**0`` was undefined. .. function:: sqrt(x) Return the square root of *x*. Trigonometric functions ----------------------- .. function:: acos(x) Return the arc cosine of *x*, in radians. .. function:: asin(x) Return the arc sine of *x*, in radians. .. function:: atan(x) Return the arc tangent of *x*, in radians. .. function:: atan2(y, x) Return ``atan(y / x)``, in radians. The result is between ``-pi`` and ``pi``. The vector in the plane from the origin to point ``(x, y)`` makes this angle with the positive X axis. The point of :func:`atan2` is that the signs of both inputs are known to it, so it can compute the correct quadrant for the angle. For example, ``atan(1)`` and ``atan2(1, 1)`` are both ``pi/4``, but ``atan2(-1, -1)`` is ``-3*pi/4``. .. function:: cos(x) Return the cosine of *x* radians. .. function:: hypot(x, y) Return the Euclidean norm, ``sqrt(x*x + y*y)``. This is the length of the vector from the origin to point ``(x, y)``. .. function:: sin(x) Return the sine of *x* radians. .. function:: tan(x) Return the tangent of *x* radians. Angular conversion ------------------ .. function:: degrees(x) Convert angle *x* from radians to degrees. .. function:: radians(x) Convert angle *x* from degrees to radians. Hyperbolic functions -------------------- .. function:: acosh(x) Return the inverse hyperbolic cosine of *x*. .. versionadded:: 2.6 .. function:: asinh(x) Return the inverse hyperbolic sine of *x*. .. versionadded:: 2.6 .. function:: atanh(x) Return the inverse hyperbolic tangent of *x*. .. versionadded:: 2.6 .. function:: cosh(x) Return the hyperbolic cosine of *x*. .. function:: sinh(x) Return the hyperbolic sine of *x*. .. function:: tanh(x) Return the hyperbolic tangent of *x*. Special functions ----------------- .. function:: erf(x) Return the error function at *x*. .. versionadded:: 2.7 .. function:: erfc(x) Return the complementary error function at *x*. .. versionadded:: 2.7 .. function:: gamma(x) Return the Gamma function at *x*. .. versionadded:: 2.7 .. function:: lgamma(x) Return the natural logarithm of the absolute value of the Gamma function at *x*. .. versionadded:: 2.7 Constants --------- .. data:: pi The mathematical constant π = 3.141592..., to available precision. .. data:: e The mathematical constant e = 2.718281..., to available precision. .. impl-detail:: The :mod:`math` module consists mostly of thin wrappers around the platform C math library functions. Behavior in exceptional cases follows Annex F of the C99 standard where appropriate. The current implementation will raise :exc:`ValueError` for invalid operations like ``sqrt(-1.0)`` or ``log(0.0)`` (where C99 Annex F recommends signaling invalid operation or divide-by-zero), and :exc:`OverflowError` for results that overflow (for example, ``exp(1000.0)``). A NaN will not be returned from any of the functions above unless one or more of the input arguments was a NaN; in that case, most functions will return a NaN, but (again following C99 Annex F) there are some exceptions to this rule, for example ``pow(float('nan'), 0.0)`` or ``hypot(float('nan'), float('inf'))``. Note that Python makes no effort to distinguish signaling NaNs from quiet NaNs, and behavior for signaling NaNs remains unspecified. Typical behavior is to treat all NaNs as though they were quiet. .. versionchanged:: 2.6 Behavior in special cases now aims to follow C99 Annex F. In earlier versions of Python the behavior in special cases was loosely specified. .. seealso:: Module :mod:`cmath` Complex number versions of many of these functions.