嵌套的 for 循环被忽略

Question

我有一个嵌套的 for 循环，但是它被忽略了，我不知道为什么。

import pandas as pd
import shutil
import os
import glob

source_dir = r'C:\Users\Ahmed_Abdelmuniem\Desktop\GLift'
target_dir = r'C:\Users\Ahmed_Abdelmuniem\Desktop\TAfternoon'

file_names = glob.glob(os.path.join(source_dir, '*.html'))

for file_name in file_names:

    table = pd.read_html(file_name)
    print ('tables found:', len(table))
    for table in file_name:
        filtered_table = [df for df in table if len(df) > 2]
        for df in filtered_table:
            comp = df.iat[1, 0]
            if comp == 'SLS':
                name = df.iat[0,0]
                print (name)

输出如下：

:\Users\Ahmed_Abdelmuniem\AppData\Local\Programs\Python\Python39\python.exe "C:/Users/Ahmed_Abdelmuniem/PycharmProjects/File mover V2.0/main.py"
tables found: 73
tables found: 73
tables found: 71
tables found: 72
tables found: 123
tables found: 124
tables found: 123
tables found: 124
tables found: 123
tables found: 72
tables found: 72
tables found: 123
tables found: 121
tables found: 122
tables found: 119
tables found: 125
tables found: 124
tables found: 121
tables found: 121
tables found: 120
tables found: 122
tables found: 121

Process finished with exit code 0

如您所见，它只执行第一个 for 循环，而不是第二个，因为它不打印 name 变量。

编辑：为了澄清，我已经证明代码在不嵌套时可以工作。

这是单独工作以提取数据的代码，但是在嵌套时它不起作用。

import pandas as pd
import xlwt
from xlwt import Workbook
from openpyxl import load_workbook
fn = r'C:\Users\Ahmed_Abdelmuniem\PycharmProjects\Pandas Parser\Survey.xlsx'



file = r'C:\Users\Ahmed_Abdelmuniem\Desktop\XXX.html'
table = pd.read_html(file)


i=3

filtered_table = [df for df in table if len(df) > 2]

for df in filtered_table:
    comp = df.iat[1,0]

    if comp == 'SLS' :
        name = df.iat[0,0]
        print (name)

这是另一个代码的输出，表明那里确实有数据。

C:\Users\Ahmed_Abdelmuniem\AppData\Local\Programs\Python\Python39\python.exe "C:/Users/Ahmed_Abdelmuniem/PycharmProjects/Pandas Parser/main.py"
INW
SPL

Process finished with exit code 0

Answer 1

在您的以下工作代码中

file = r'C:\Users\Ahmed_Abdelmuniem\Desktop\XXX.html'
table = pd.read_html(file)

filtered_table = [df for df in table if len(df) > 2]

for df in filtered_table:
    comp = df.iat[1,0]

    if comp == 'SLS' :
        name = df.iat[0,0]
        print (name)

你在做，

1. 用pd.read_html(file)读表
2. 使用[df for df in table if len(df) > 2] 过滤表

然而，在你的嵌套循环中，你正在做

1. 用pd.read_html(file_name)读表
2. 未知的输入for table in file_name。
3. 使用[df for df in table if len(df) > 2] 过滤表

for file_name in file_names:
    table = pd.read_html(file_name)
    print ('tables found:', len(table))
    for table in file_name:
        filtered_table = [df for df in table if len(df) > 2] 
        #                               ^
        #                               |
        #                              table here is file_name
        for df in filtered_table:
            comp = df.iat[1, 0]
            if comp == 'SLS':
                name = df.iat[0,0]
                print (name)

您可能需要删除 for table in file_name 行

for file_name in file_names:

    table = pd.read_html(file_name)
    print ('tables found:', len(table))

    filtered_table = [df for df in table if len(df) > 2]
    for df in filtered_table:
        comp = df.iat[1, 0]
        if comp == 'SLS':
            name = df.iat[0,0]
            print (name)