我找到了很多关于如何抑制大熊猫科学记数法的答案，但我如何启用呢？我找到了pd.set_option('precision', 2)选项，但它没有将大数字变成科学记数法。
例如，我希望将数字123066.14格式化为1.23E+5。我使用的是pandas.DataFrame，在导出/打印时设置整列的格式会很有用。
答案 0 :(得分：8)
好的，我想出来了，您可以使用set_option并将格式字符串传递给选项/*-
* Copyright (c) 2008 Fredrik Lindberg - http://www.shapeshifter.se
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/
/*
* UUID (RFC4122) Generator
* http://tools.ietf.org/html/rfc4122
*
* Implements version 1, 3, 4 and 5
*/
class GEN_UUID {
/* UUID versions */
const UUID_TIME = 1; /* Time based UUID */
const UUID_NAME_MD5 = 3; /* Name based (MD5) UUID */
const UUID_RANDOM = 4; /* Random UUID */
const UUID_NAME_SHA1 = 5; /* Name based (SHA1) UUID */
/* UUID formats */
const FMT_FIELD = 100;
const FMT_STRING = 101;
const FMT_BINARY = 102;
const FMT_QWORD = 1; /* Quad-word, 128-bit (not impl.) */
const FMT_DWORD = 2; /* Double-word, 64-bit (not impl.) */
const FMT_WORD = 4; /* Word, 32-bit (not impl.) */
const FMT_SHORT = 8; /* Short (not impl.) */
const FMT_BYTE = 16; /* Byte */
const FMT_DEFAULT = 16;
public function __construct()
{
}
/* Field UUID representation */
static private $m_uuid_field = array(
'time_low' => 0, /* 32-bit */
'time_mid' => 0, /* 16-bit */
'time_hi' => 0, /* 16-bit */
'clock_seq_hi' => 0, /* 8-bit */
'clock_seq_low' => 0, /* 8-bit */
'node' => array() /* 48-bit */
);
static private $m_generate = array(
self::UUID_TIME => "generateTime",
self::UUID_RANDOM => "generateRandom",
self::UUID_NAME_MD5 => "generateNameMD5",
self::UUID_NAME_SHA1 => "generateNameSHA1"
);
static private $m_convert = array(
self::FMT_FIELD => array(
self::FMT_BYTE => "conv_field2byte",
self::FMT_STRING => "conv_field2string",
self::FMT_BINARY => "conv_field2binary"
),
self::FMT_BYTE => array(
self::FMT_FIELD => "conv_byte2field",
self::FMT_STRING => "conv_byte2string",
self::FMT_BINARY => "conv_byte2binary"
),
self::FMT_STRING => array(
self::FMT_BYTE => "conv_string2byte",
self::FMT_FIELD => "conv_string2field",
self::FMT_BINARY => "conv_string2binary"
),
);
/* Swap byte order of a 32-bit number */
static private function swap32($x) {
return (($x & 0x000000ff) << 24) | (($x & 0x0000ff00) << 8) |
(($x & 0x00ff0000) >> 8) | (($x & 0xff000000) >> 24);
}
/* Swap byte order of a 16-bit number */
static private function swap16($x) {
return (($x & 0x00ff) << 8) | (($x & 0xff00) >> 8);
}
/* Auto-detect UUID format */
static private function detectFormat($src) {
if (is_string($src))
return self::FMT_STRING;
else if (is_array($src)) {
$len = count($src);
if ($len == 1 || ($len % 2) == 0)
return $len;
else
return (-1);
}
else
return self::FMT_BINARY;
}
/*
* Public API, generate a UUID of 'type' in format 'fmt' for
* the given namespace 'ns' and node 'node'
*/
static public function generate($type=self::UUID_RANDOM, $fmt = self::FMT_STRING, $node = "", $ns = "") {
$func = self::$m_generate[$type];
if (!isset($func))
return null;
$conv = self::$m_convert[self::FMT_FIELD][$fmt];
$uuid = self::$func($ns, $node);
return self::$conv($uuid);
}
/*
* Public API, convert a UUID from one format to another
*/
static public function convert($uuid, $from, $to) {
$conv = self::$m_convert[$from][$to];
if (!isset($conv))
return ($uuid);
return (self::$conv($uuid));
}
/*
* Generate an UUID version 4 (pseudo random)
*/
static private function generateRandom($ns, $node) {
$uuid = self::$m_uuid_field;
$uuid['time_hi'] = (4 << 12) | (mt_rand(0, 0x1000));
$uuid['clock_seq_hi'] = (1 << 7) | mt_rand(0, 128);
$uuid['time_low'] = mt_rand(0, 0xffff) + (mt_rand(0, 0xffff) << 16);
$uuid['time_mid'] = mt_rand(0, 0xffff);
$uuid['clock_seq_low'] = mt_rand(0, 255);
for ($i = 0; $i < 6; $i++)
$uuid['node'][$i] = mt_rand(0, 255);
return ($uuid);
}
/*
* Generate UUID version 3 and 5 (name based)
*/
static private function generateName($ns, $node, $hash, $version) {
$ns_fmt = self::detectFormat($ns);
$field = self::convert($ns, $ns_fmt, self::FMT_FIELD);
/* Swap byte order to keep it in big endian on all platforms */
$field['time_low'] = self::swap32($field['time_low']);
$field['time_mid'] = self::swap16($field['time_mid']);
$field['time_hi'] = self::swap16($field['time_hi']);
/* Convert the namespace to binary and concatenate node */
$raw = self::convert($field, self::FMT_FIELD, self::FMT_BINARY);
$raw .= $node;
/* Hash the namespace and node and convert to a byte array */
$val = $hash($raw, true);
$tmp = unpack('C16', $val);
foreach (array_keys($tmp) as $key)
$byte[$key - 1] = $tmp[$key];
/* Convert byte array to a field array */
$field = self::conv_byte2field($byte);
$field['time_low'] = self::swap32($field['time_low']);
$field['time_mid'] = self::swap16($field['time_mid']);
$field['time_hi'] = self::swap16($field['time_hi']);
/* Apply version and constants */
$field['clock_seq_hi'] &= 0x3f;
$field['clock_seq_hi'] |= (1 << 7);
$field['time_hi'] &= 0x0fff;
$field['time_hi'] |= ($version << 12);
return ($field);
}
static private function generateNameMD5($ns, $node) {
return self::generateName($ns, $node, "md5",
self::UUID_NAME_MD5);
}
static private function generateNameSHA1($ns, $node) {
return self::generateName($ns, $node, "sha1",
self::UUID_NAME_SHA1);
}
/*
* Generate UUID version 1 (time based)
*/
static private function generateTime($ns, $node) {
$uuid = self::$m_uuid_field;
/*
* Get current time in 100 ns intervals. The magic value
* is the offset between UNIX epoch and the UUID UTC
* time base October 15, 1582.
*/
$tp = gettimeofday();
$time = ($tp['sec'] * 10000000) + ($tp['usec'] * 10) +
0x01B21DD213814000;
$uuid['time_low'] = $time & 0xffffffff;
/* Work around PHP 32-bit bit-operation limits */
$high = intval($time / 0xffffffff);
$uuid['time_mid'] = $high & 0xffff;
$uuid['time_hi'] = (($high >> 16) & 0xfff) | (self::UUID_TIME << 12);
/*
* We don't support saved state information and generate
* a random clock sequence each time.
*/
$uuid['clock_seq_hi'] = 0x80 | mt_rand(0, 64);
$uuid['clock_seq_low'] = mt_rand(0, 255);
/*
* Node should be set to the 48-bit IEEE node identifier, but
* we leave it for the user to supply the node.
*/
for ($i = 0; $i < 6; $i++)
$uuid['node'][$i] = ord(substr($node, $i, 1));
return ($uuid);
}
/* Assumes correct byte order */
static private function conv_field2byte($src) {
$uuid[0] = ($src['time_low'] & 0xff000000) >> 24;
$uuid[1] = ($src['time_low'] & 0x00ff0000) >> 16;
$uuid[2] = ($src['time_low'] & 0x0000ff00) >> 8;
$uuid[3] = ($src['time_low'] & 0x000000ff);
$uuid[4] = ($src['time_mid'] & 0xff00) >> 8;
$uuid[5] = ($src['time_mid'] & 0x00ff);
$uuid[6] = ($src['time_hi'] & 0xff00) >> 8;
$uuid[7] = ($src['time_hi'] & 0x00ff);
$uuid[8] = $src['clock_seq_hi'];
$uuid[9] = $src['clock_seq_low'];
for ($i = 0; $i < 6; $i++)
$uuid[10+$i] = $src['node'][$i];
return ($uuid);
}
static private function conv_field2string($src) {
$str = sprintf(
'%08x-%04x-%04x-%02x%02x-%02x%02x%02x%02x%02x%02x',
($src['time_low']), ($src['time_mid']), ($src['time_hi']),
$src['clock_seq_hi'], $src['clock_seq_low'],
$src['node'][0], $src['node'][1], $src['node'][2],
$src['node'][3], $src['node'][4], $src['node'][5]);
return ($str);
}
static private function conv_field2binary($src) {
$byte = self::conv_field2byte($src);
return self::conv_byte2binary($byte);
}
static private function conv_byte2field($uuid) {
$field = self::$m_uuid_field;
$field['time_low'] = ($uuid[0] << 24) | ($uuid[1] << 16) |
($uuid[2] << 8) | $uuid[3];
$field['time_mid'] = ($uuid[4] << 8) | $uuid[5];
$field['time_hi'] = ($uuid[6] << 8) | $uuid[7];
$field['clock_seq_hi'] = $uuid[8];
$field['clock_seq_low'] = $uuid[9];
for ($i = 0; $i < 6; $i++)
$field['node'][$i] = $uuid[10+$i];
return ($field);
}
static public function conv_byte2string($src) {
$field = self::conv_byte2field($src);
return self::conv_field2string($field);
}
static private function conv_byte2binary($src) {
$raw = pack('C16', $src[0], $src[1], $src[2], $src[3],
$src[4], $src[5], $src[6], $src[7], $src[8], $src[9],
$src[10], $src[11], $src[12], $src[13], $src[14], $src[15]);
return ($raw);
}
static private function conv_string2field($src) {
$parts = sscanf($src, '%x-%x-%x-%x-%02x%02x%02x%02x%02x%02x');
$field = self::$m_uuid_field;
$field['time_low'] = ($parts[0]);
$field['time_mid'] = ($parts[1]);
$field['time_hi'] = ($parts[2]);
$field['clock_seq_hi'] = ($parts[3] & 0xff00) >> 8;
$field['clock_seq_low'] = $parts[3] & 0x00ff;
for ($i = 0; $i < 6; $i++)
$field['node'][$i] = $parts[4+$i];
return ($field);
}
static private function conv_string2byte($src) {
$field = self::conv_string2field($src);
return self::conv_field2byte($field);
}
static private function conv_string2binary($src) {
$byte = self::conv_string2byte($src);
return self::conv_byte2binary($byte);
}
}
：
'display.float_format'修改
匹配您想要的输出：
In [76]:
pd.set_option('display.float_format', '{:.2g}'.format)
In [78]:
pd.Series(data=[0.00000001])
Out[78]:
0 1e-08
dtype: float64