在“For”循环内调用一个函数会引发一个NameError [英] Calling a function inside 'For' loop throws a NameError
问题描述
我正在尝试从FOR循环中调用一个函数,但出现错误:
test()
NameError:name'test'未定义
代码如下:
$来自selenium import webdriver的$ b从selenium.common.exceptions导入NoSuchElementException
从selenium.webdriver.common.keys导入键
导入时间
从lxml导入html
导入请求
导入xlwt
browser = webdriver.Firefox()#获取本地会话的firefox
#0等待页面加载
browser.implicitly_wait(3)#3秒应该够了。如果没有,增加
browser.get(http://ae.bizdirlib.com/taxonomy/term/1493)#加载页
links = browser.find_elements_by_css_selector(h2 $ a
链接中的链接:
link.send_keys(Keys.CONTROL + Keys.RETURN)
link.send_keys(Keys.CONTROL + Keys.PAGE_UP)
time.sleep(5)
test()
link.send_keys(Keys.CONTROL +'w')
def test(self):#test function
elems = browser.find_elements_by_css_selector(div.content.clearfix> div> fieldset> div> ul> li> span)
elem in elems:
print elem.text
elem1 = browser.find_elements_by_css_selector(div.content.clearfix> div> fieldset> div> ul> li> a)
elem1中的elems21
print elems21.text
返回0
所以我想调用该函数,当函数调用时,我希望数据被复制/粘贴到Excel中。
有人可以帮助我增强代码吗?
你必须创建一个函数对象
才能使用它。在你的情况下,你调用一个函数,但它还不存在,因此没有定义。正如Kevin所说,定义函数,然后尝试调用它。
UPD:我不能添加评论,所以我在这里更新。 Mark Lutz在学习Python书中详细描述了它的功能,功能如何工作,什么是 def
,当您调用函数时会发生什么。但是我认为任何其他的Python书都会这样做。
UPD:写评论并不容易,所以我更新了答案。
如上所述,问题是你调用它后定义函数。例如,假设我想编写一个写有乐趣的任何名称的程序。为简单起见,程序中给出了名称。
选项1:如果我写的程序就像你的意思1)调用函数2)定义一个函数我将得到一个名称错误,就像你得到的。
程序:
greet ='玩得开心'
print(greet + name '))#我调用一个函数'name'
def name(x):#我定义一个函数
return str(x)
输出将为:
追溯(最多最近的电话最后):
文件C:/Users/nikolay.dudaev/Documents/Private/deffun2.py,第3行,< module>
print(greet + name('John'))
NameError:name'name'未定义
我需要做的是更改功能定义和调用函数的位置:
greet = '
def name(x):#定义一个函数
return str(x)
print(greet + name('John' ))#我调用一个函数'name'
现在的输出是:
======= RESTART:C:/Users/nikolay.dudaev/Documents/Private/deffun2.py ====== =
玩得开心,John
>>>
你去!
复制什么你在 def
之后,将它粘贴在之前
循环,它应该可以工作(虽然我没有尝试你的代码) 。
I'm trying to call a function from a FOR loop but get the error:
test()
NameError: name 'test' is not defined
The code is given below:
from selenium import webdriver
from selenium.common.exceptions import NoSuchElementException
from selenium.webdriver.common.keys import Keys
import time
from lxml import html
import requests
import xlwt
browser = webdriver.Firefox() # Get local session of firefox
# 0 wait until the pages are loaded
browser.implicitly_wait(3) # 3 secs should be enough. if not, increase it
browser.get("http://ae.bizdirlib.com/taxonomy/term/1493") # Load page
links = browser.find_elements_by_css_selector("h2 > a")
for link in links:
link.send_keys(Keys.CONTROL + Keys.RETURN)
link.send_keys(Keys.CONTROL + Keys.PAGE_UP)
time.sleep(5)
test()
link.send_keys(Keys.CONTROL + 'w')
def test(self):#test function
elems = browser.find_elements_by_css_selector("div.content.clearfix > div > fieldset> div > ul > li > span")
for elem in elems:
print elem.text
elem1 = browser.find_elements_by_css_selector("div.content.clearfix>div>fieldset>div>ul>li>a")
for elems21 in elem1:
print elems21.text
return 0
So I want to call the function and when the function is called I want the data to be copy/pasted into Excel.
Can somebody help me to enhance the code ?
You have to create a function object
before you can use it. In your case you call a function but it is not yet existing hence not defined. As Kevin said, define the function and then try to call it.
UPD: I cannot add comments so I update it here. Mark Lutz in his "Learning Python" book describes it in a great detail, how functions work, what def
does and what happens when you call a function. But I assume any other Python book will do the same.
UPD: It is not easy to write comments, so I update the answer.
As said the problem is that you define function after you call it. For example, let's assume I want to write a program which writes "Have fun, " + any name. For simplicity name is given in the program. Option 1: If I write the program like you did meaning 1) call a function 2) define a function I will get an NameError exactly like you get.
Program:
greet = 'Have fun, '
print(greet + name('John')) # I call a function 'name'
def name(x): # I define a function
return str(x)
The output will be:
Traceback (most recent call last):
File "C:/Users/nikolay.dudaev/Documents/Private/deffun2.py", line 3, in <module>
print(greet + name('John'))
NameError: name 'name' is not defined
ALL that I need to do is change places of function definition and calling a function:
greet = 'Have fun, '
def name(x): # I define a function
return str(x)
print(greet + name('John')) # I call a function 'name'
And now the output is:
======= RESTART: C:/Users/nikolay.dudaev/Documents/Private/deffun2.py =======
Have fun, John
>>>
Here you go!
Copy what you have after def
and paste it before your for
loop and it should work (though I did not try your code).
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