在Python中，从url提取的表中选择子标题的panda语法是什么？

Question

Headers:          Volume       Energy        Enthalpy      
Subheaders:       vf  vg       uf  ug      hf  hfg  hg

例如：如果我想选择[焓，hfg]，我会期望如下：

df = pd.read_html('url', header=[2,1])

I used this post as a reference，但这不起作用

import pandas as pd

def get_data_from_webpage(url):# This returns a list of dataframes
    
    t_table = pd.read_html(url, header=1)
   
    return t_table[0]

result = get_data_from_webpage('http://ouopentextbooks.org/thermodynamics/saturation-properties-temperature-table/') # Url with table being passed through function.

print(result) 

从这里，我想选择temp列作为键，然后将相应行的其余部分放入查找表中。然后，当用户输入键时，它输出相应的值行

最终结果如下：

用户输入：20

输出：vf、uf、hf和sf值

Answer 1

好的，我做了一个解决方案。但是，您可能必须首先执行pip install Unidecode来安装必要的库

我使用字母表作为索引，以避免混淆用户，因为列是数字的

以下是输出：

List of available temperatures:

AA) 000.01
AB) 005.00
AC) 010.00
AD) 015.00
AE) 020.00
AF) 025.00
AG) 030.00
AH) 035.00
AI) 040.00
AJ) 045.00
AK) 050.00
AL) 055.00
AM) 060.00
AN) 065.00
AO) 070.00
AP) 075.00
AQ) 080.00
AR) 085.00
AS) 090.00
AT) 095.00
AU) 100.00
AV) 110.00
AW) 120.00
AX) 130.00
AY) 140.00
AZ) 150.00
BA) 160.00
BB) 170.00
BC) 180.00
BD) 190.00
BE) 200.00
BF) 210.00
BG) 220.00
BH) 230.00
BI) 240.00
BJ) 250.00
BK) 260.00
BL) 270.00
BM) 280.00
BN) 290.00
BO) 300.00
BP) 310.00
BQ) 320.00
BR) 330.00
BS) 340.00
BT) 350.00
BU) 360.00
BV) 370.00
BW) 373.95

Enter a temperature (in degrees celsius) from the available options above: 250

vf is: 0.0012519999999999999
uf is: 1080.8
hf is: 1085.8
sf is: 2.7935

代码如下：

import pandas as pd
import os
from unidecode import unidecode
import itertools
import string
import sys

def file_len(fname):
    with open(fname) as fp:
        for i, line in enumerate(fp):
            pass
    return i + 1

def excel_cols():
    n = 1
    while True:
        yield from (''.join(group) for group in itertools.product(string.ascii_uppercase, repeat=n))
        n += 1

def remove_and_exit(temp13,temp12=0):
    try:
        os.remove("test.csv")
    except:
        pass
    if temp13:
        sys.exit(temp12)

def get_data_from_webpage(url):# This returns a list of dataframes

    t_table = pd.read_html(url, header=1)

    return t_table[0]

result = get_data_from_webpage('http://ouopentextbooks.org/thermodynamics/saturation-properties-temperature-table/') # Url with table being passed through function.

result.index.rename('index', inplace=True)


new_columns = result.columns.values
for temp1 in range(len(new_columns)):
    new_columns[temp1] = unidecode(new_columns[temp1])
result.columns  = new_columns

remove_and_exit(False)

result.to_csv("test.csv", sep=',', encoding='utf-8')

temp2 = []

with open("test.csv") as file_in:
    for line in file_in:
        temp2.append(line.strip())

temp5 = list(itertools.islice(excel_cols(), file_len("test.csv")+26))
temp5 = temp5[26:-1]

temp6 = -1 #before decimal
temp7 = -1 #after decimal

print("List of available temperatures:\n")
for temp3 in range(len(temp2)): #temp5[temp3-1]
    if temp3 == 0:
        continue
    if (len(temp2[temp3].split(",")[1].split(".")[0])) > temp6:
        temp6 = len(temp2[temp3].split(",")[1].split(".")[0])
    if (len(temp2[temp3].split(",")[1].split(".")[1])) > temp7:
        temp7 = len(temp2[temp3].split(",")[1].split(".")[1])

for temp8 in range(len(temp2)): #temp5[temp8-1]
    if temp8 == 0:
        continue
    print(temp5[temp8-1]+") "+temp2[temp8].split(",")[1].split(".")[0].zfill(temp6)+"."+temp2[temp8].split(",")[1].split(".")[1].ljust(temp7, '0'))


temp4 = input("\nEnter a temperature (in degrees celsius) from the available options above: ")

try:
    temp9 = float(temp4)
except:
    print("\nYou did not enter a temperature (in degrees celsius)")
    remove_and_exit(True,11)
temp11 = False
for temp10 in range(len(temp2)):
    if temp10 == 0:
        continue
    if temp9 == float(temp2[temp10].split(",")[1]):
        print("")
        print("vf is: "+temp2[temp10].split(",")[3])
        print("uf is: "+temp2[temp10].split(",")[5])
        print("hf is: "+temp2[temp10].split(",")[7])
        print("sf is: "+temp2[temp10].split(",")[10])
        temp11 = True
        break
if not temp11:
    print("\nYou did not enter a value from the available options above")
    remove_and_exit(True,1761)
remove_and_exit(True)