Python-For Loop if语句跳至Selenium中的下一个迭代

Question

I'm using selenium to iterate through the different combinations of a variable's parameters and download the data from a website. However, the for loop function stops working when there's no data; I also notice when selenium stops the webpage contains a text labeled "Cannot produce results.". Thus, I figured to use an if statement with selenium to search for "Cannot produce results" and skip to the next loop if the aforementioned text were found. An example would be something like this:

import os
from selenium import webdriver
import zipfile
import pandas as pd
import time

for i in to_loop:
    # directories
    link = 'http://www.gaez.iiasa.ac.at/w/ctrl?
_flow=Vwr&_view=Welcome&idAS=0&idFS=0&fieldmain=main_&idPS=0'

    ## Access Chrome Driver to use selenium
    # Define Download Directory
    chrome_options = webdriver.ChromeOptions()
    prefs = {'download.default_directory': 'C:/.../Download'}
    chrome_options.add_experimental_option('prefs', prefs)
    driver = webdriver.Chrome(
        executable_path='C:/.../chromedriver.exe',
        chrome_options=chrome_options)
    driver.get(link)

    # Enter username and password
    driver.find_element_by_name('_username').send_keys(username)
    driver.find_element_by_name('_password').send_keys(password)
    driver.find_element_by_id('buttonSubmit__login').click()

    # Click on Suitability and Potential Yield link
    driver.find_element_by_name('_targetfieldmain=main_py&_...').click()

    # Click on Agro-ecological suitability and productivity link
    driver.find_element_by_name('&fieldmain=main_py&idPS=0&...').click()
    # Click on Agro-ecological suitability and productivity list
    driver.find_element_by_css_selector('input[value="
{}"]'.format(i[0])).click()
    # Click on crop link
    driver.find_element_by_css_selector("input.linksubmit[value=\"▸ 
Crop\"]").click()
    AES_and_P = i[0]

    driver.find_element_by_css_selector('input[value="
{}"]'.format(i[1])).click()
    # Click on Water Supply Link
    driver.find_element_by_css_selector("input.linksubmit[value=\"▸ Water 
Supply\"]").click()
    Crop = i[1]

    driver.find_element_by_css_selector('input[value="
{}"]'.format(i[2])).click()
    # Click on Input Level Link
    driver.find_element_by_css_selector("input.linksubmit[value=\"▸ Input 
Level\"]").click()
    Water_Supply = i[2]

    driver.find_element_by_css_selector('input[value="
{}"]'.format(i[3])).click()
    Input_Level = i[3]

    # If statement to skip to next loop if text found
    data_check = driver.find_elements_by_partial_link_text('Cannot produce 
results.')
    if data_check[0].is_displayed():
        continue

    # Click on Time Period and Select Baseline
    driver.find_element_by_css_selector("input.linksubmit[value=\"▸ Time 
Period\"]").click()
    driver.find_element_by_css_selector("input.linksubmit[value=\"1961-
1990\"]").click()
    # Click on Geographic Areas Link
    driver.find_element_by_css_selector("input.linksubmit[value=\"▸ 
Geographic Areas\"]").click()
    # Unselect all countries
    driver.find_element_by_xpath('//*[@id="fieldareaList__pln-1"]').click()
    # Close tab for Northern Africa
    driver.find_element_by_xpath('//*[@id="rg1-66-Northern 
Africa"]/span').click()
    # Wait 1 second
    time.sleep(1)
    # Click geographic area then country
    driver.find_element_by_xpath('//label[text()="{}"]/following-
sibling::span'.format(geographic_area)).click()
    driver.find_element_by_xpath('//label[text()="
{}"]'.format(country)).click()
    # Click on Map Link
    driver.find_element_by_css_selector("input.linksubmit[value=\"▸ 
Map\"]").click()
    # Download Data
    driver.find_element_by_xpath('//*[@id="buttons"]/a[4]/img').click()

    # Wait 2 seconds
    time.sleep(2)

    # Download blah blah
    path = 'C:/.../Download'
    destination_folder = 'C:/.../CSV_Files'
    file_list = [os.path.join(path, f) for f in os.listdir(path)]
    time_sorted_list = sorted(file_list, key=os.path.getmtime)
    file_name = time_sorted_list[-1]
    # decompress the zipped file here
    myzip = zipfile.ZipFile(file_name)

    # Wait 1 second
    time.sleep(1)

    myzip.extract('data.asc', destination_folder)

    # Save data.asc file as .csv and rename reflects download selections
    newfilename = country + Crop + Water_Supply + Input_Level + AES_and_P
    df = pd.read_table(os.path.join(destination_folder, 'data.asc'), 
sep="\s+", skiprows=6, header=None)
    df.to_csv(os.path.join(destination_folder, '{}.csv'.format(newfilename)))

    # Delete downloaded data.asc file
    delete_data_file = "C:/.../CSV_Files/data.asc"
    # if file exists, delete it
    if os.path.isfile(delete_data_file):
        os.remove(delete_data_file)
    else:  # Show error
        print("Error: %s file not found" % delete_data_file)

    driver.close()

However, this code simply stops the function at continue, doesn't complete the download portion of the code, and iterates through the rest of the loop. Any idea with how to solve this? Also, please let me know if the question is confusing.

Answer 1

After our discussion in the comments I believe I see at least part of your issue. The python continue keyword does not mean "continue with the rest of control flow" it means to "continue to the next iteration of the loop, skip everything after".

For example, in the following piece of python code:

a = []
for i in range(10):
    if i == 5:
        continue
    a.append(i)

print(a)

The result would be:

[0, 1, 2, 3, 4, 6, 7, 8, 9]

And not, using your previous logic

[5]

Thus to fix your code on the continue, you would need to flip the logic so that you skip if the condition is not true, for example:

 if not data_check[0].is_displayed():
     continue

While I've personally never encountered someone who had made the same error as you, I certainly emphasize as semantically it does appear to make more sense that "continue" would refer to continuing on with the next part of the program. Pythons choice in continue comes in large part from historical usage of continue as a keyword, particularly in C . In this case, we can see continue as more of an extension of the break statement into a "skip".