how to cast a variable in xpath python

问题

from lxml import html
import requests

pagina = 'http://www.beleggen.nl/amx'
page = requests.get(pagina)
tree = html.fromstring(page.text)

aandeel = tree.xpath('//a[@title="Imtech"]/text()')
print aandeel

This part works, but I want to read multiple lines with different titles, is it possible to change the "Imtech" part to a variable?

Something like this, it obviously doesnt work, but where did I go wrong? Or is it not quite this easy?

FondsName = "Imtech"
aandeel = tree.xpath('//a[@title="%s"]/text()')%(FondsName)
print aandeel

回答1:

You were almost right:

variabelen = [var1,var2,var3]
for var in variabelen:
    aandeel = tree.xpath('//a[@title="%s"]/text()' % var)

回答2:

XPath allows $variables and lxml's .xpath() method allows for supplying values for those variables as keyword arguments: .xpath('$variable', variable='my value')

Using your example, here's how you'd do it:

fonds_name = 'Imtech'
aandeel = tree.xpath('//a[@title="$title"]/text()', title=fonds_name)
print(aandeel)

See lmxl's docs for more info: http://lxml.de/xpathxslt.html#the-xpath-method

回答3:

Almost...

FondsName = "Imtech"
aandeel = tree.xpath('//a[@title="%s"]/text()'%FondsName)
print aandeel

来源：https://stackoverflow.com/questions/26297410/how-to-cast-a-variable-in-xpath-python