Convert Scientific Notation to Float

问题

Encountered a problem whereby my JSON data gets printed as a scientific notation instead of a float.

import urllib2
import json
import sys

url = 'https://bittrex.com/api/v1.1/public/getmarketsummary?market=btc-quid'
json_obj = urllib2.urlopen(url)
QUID_data = json.load(json_obj)

QUID_MarketName_Trex = QUID_data["result"][0]["MarketName"][4:9]
QUID_Last_Trex = QUID_data["result"][0]["Last"]
QUID_High_Trex = QUID_data["result"][0]["High"]
QUID_Low_Trex = QUID_data["result"][0]["Low"]
QUID_Volume_Trex = QUID_data["result"][0]["Volume"]
QUID_BaseVolume_Trex = QUID_data["result"][0]["BaseVolume"]
QUID_TimeStamp_Trex = QUID_data["result"][0]["TimeStamp"]
QUID_Bid_Trex = QUID_data["result"][0]["Bid"]
QUID_Ask_Trex = QUID_data["result"][0]["Ask"]
QUID_OpenBuyOrders_Trex = QUID_data["result"][0]["OpenBuyOrders"]
QUID_OpenSellOrders_Trex = QUID_data["result"][0]["OpenSellOrders"]
QUID_PrevDay_Trex = QUID_data["result"][0]["PrevDay"]
QUID_Created_Trex = QUID_data["result"][0]["Created"]
QUID_Change_Trex = ((QUID_Last_Trex - QUID_PrevDay_Trex)/ QUID_PrevDay_Trex)*100
QUID_Change_Var = str(QUID_Change_Trex)
QUID_Change_Final = QUID_Change_Var[0:5] + '%'

print QUID_Last_Trex   

It prints the following value; 1.357e-05. I need this to be a float with 8 chars behind the decimal (0.00001370)

As you can see here --> http://i.imgur.com/FCVM1UN.jpg, my GUI displays the first row correct (using the exact same code).

回答1:

You are looking at the default str() formatting of floating point numbers, where scientific notation is used for sufficiently small or large numbers.

You don't need to convert this, the value itself is a proper float. If you need to display this in a different format, format it explicitly:

>>> print 0.00001357
1.357e-05
>>> print format(0.00001357, 'f')
0.000014
>>> print format(0.00001357, '.8f')
0.00001357

Here the f format always uses fixed point notation for the value. The default precision is 6 digits; the .8 instructs the f formatter to show 8 digits instead.

The default string format is essentially the same as format(fpvalue, '.12g'); the g format uses either a scientific or fixed point presentation depending on the exponent of the number.

回答2:

You can use print formatting:

x = 1.357e-05    
print('%f' % x)

Edit:

print('%.08f' % x)

来源：https://stackoverflow.com/questions/25099626/convert-scientific-notation-to-float