使用Pandas时遇列表索引越界，如何正确访问单个索引？

问题背景 #

我正在开发一个解析Excel表格数据的Python脚本，目标是通过零件号找到对应行号，再获取该行其他列的单元格值。

当前代码 #

from pathlib import Path
import pandas as pd
import re

## OPENING FILES ##
# Opens the path to the prints
entries = Path(r'C:\Users\jmcintosh\LIDT Project (copy)\LIDT Project\Solidworks Test (DEV)')
# Opens Excel sheet for reading
xlEntries = pd.read_excel(r'C:\Users\jmcintosh\LIDT Project (copy)\LIDT Project\LIDT New Webspec         Titles 2.0.xlsx')


## Variable Definitions ## (Stick to CamelCase "firstLast")
partNumbers = [] # Make partNumbers the array for partnumbers, gathers the names as well as the partnumbers
specName = []    # Create an array to hold the specification names--this becomes the value of the cells
rowNumber = []   # Array for desired row numbers
specValue = []   # Array for desired specifications

# A 'for' loop that allows iteration through the directory of names.
for entry in entries.iterdir():
        partNumbertemp = re.findall('[0-9]+', entry.name)
        partNumbers.append(int(partNumbertemp[0]))    # Appends the array with the regex function to parse only the integers of the file name to be used later.

# A 'while' loop to remove blank file names from directory issues
while ([] in partNumbers):
        partNumbers.remove([])

fileCount = (len(partNumbers))  # Number of files being edited
rowCount = len(xlEntries['StockNumber']) # Number of rows in the Excel document
stockNumber = xlEntries['StockNumber']  # Column of stock numbers
print(partNumbers[0])

# A 'while' loop to find the row numbers and the the specification name and value of each of the desired row numbers
# Reset count for 'while' loop

k = 0
while (k<fileCount):
        rowNumbertemp = xlEntries.loc[xlEntries['StockNumber'] == partNumbers[k]].index.to_numpy()

        for row in rowNumbertemp:
            rowNumber.append(int(rowNumbertemp))
        specNametemp = xlEntries.loc[rowNumber[k],"Pat's Proposed Change"]

        for spec in specNametemp:
            specName.append(specNametemp)
        specValuetemp = xlEntries.loc[rowNumber[k],"StringValue"]

        for value in specValuetemp:
            specValue.append(specValuetemp)
        k = k + 1

        #print(len(rowNumber))
        #print(k)

报错信息 #

Traceback (most recent call last):
  File "c:\Users\jmcintosh\LIDT PRoject (copy)\LIDT Project\NEW EDMUND OPTICS LIDT\LIDT_MULTIPLE_FILE_TEST.py", line 64, in <module>
    specNametemp = xlEntries.loc[rowNumber[k],"Pat's Proposed Change"]
                                 ~~~~~~~~~^^^
IndexError: list index out of range

rowNumber输出结果 #

[2382]
[2382, 2590]
[2382, 2590, 2065]
[2382, 2590, 2065, 2383]
[2382, 2590, 2065, 2383, 2591]
[2382, 2590, 2065, 2383, 2591, 2066]
[2382, 2590, 2065, 2383, 2591, 2066, 2379]
[2382, 2590, 2065, 2383, 2591, 2066, 2379, 2380]
[2382, 2590, 2065, 2383, 2591, 2066, 2379, 2380, 2381]
[2382, 2590, 2065, 2383, 2591, 2066, 2379, 2380, 2381, 2587]
[2382, 2590, 2065, 2383, 2591, 2066, 2379, 2380, 2381, 2587, 2588]
[2382, 2590, 2065, 2383, 2591, 2066, 2379, 2380, 2381, 2587, 2588, 2589]
[2382, 2590, 2065, 2383, 2591, 2066, 2379, 2380, 2381, 2587, 2588, 2589, 2062]
[2382, 2590, 2065, 2383, 2591, 2066, 2379, 2380, 2381, 2587, 2588, 2589, 2062, 2063]
[2382, 2590, 2065, 2383, 2591, 2066, 2379, 2380, 2381, 2587, 2588, 2589, 2062, 2063, 2064]
[2382, 2590, 2065, 2383, 2591, 2066, 2379, 2380, 2381, 2587, 2588, 2589, 2062, 2063, 2064, 2384]
[2382, 2590, 2065, 2383, 2591, 2066, 2379, 2380, 2381, 2587, 2588, 2589, 2062, 2063, 2064, 2384, 2385]
[2382, 2590, 2065, 2383, 2591, 2066, 2379, 2380, 2381, 2587, 2588, 2589, 2062, 2063, 2064, 2384, 2385, 2592]
[2382, 2590, 2065, 2383, 2591, 2066, 2379, 2380, 2381, 2587, 2588, 2589, 2062, 2063, 2064, 2384, 2385, 2592, 2593]
[2382, 2590, 2065, 2383, 2591, 2066, 2379, 2380, 2381, 2587, 2588, 2589, 2062, 2063, 2064, 2384, 2385, 2592, 2593, 2067]
[2382, 2590, 2065, 2383, 2591, 2066, 2379, 2380, 2381, 2587, 2588, 2589, 2062, 2063, 2064, 2384, 2385, 2592, 2593, 2067, 163]

问题分析 #

1. rowNumber数组添加逻辑错误：代码中rowNumber.append(int(rowNumbertemp))是将整个numpy数组转成int后添加，而非遍历数组内的单个行号。虽然当前输出显示每个元素是单个数值，但如果某个零件号对应多行数据，这行代码会直接报错；同时冗余的遍历循环会导致重复添加相同值。
2. 无匹配行的处理缺失：当某个零件号在Excel中找不到对应StockNumber时，rowNumbertemp会是空数组，此时for row in rowNumbertemp循环不会执行，rowNumber没有添加任何元素，但k依然递增。当k超过rowNumber的长度时，rowNumber[k]就会触发索引越界错误。
3. 冗余代码无效：while ([] in partNumbers)循环完全无效，因为之前partNumbers.append(int(partNumbertemp[0]))如果partNumbertemp是空数组，会直接触发索引错误，根本不会将空数组添加到partNumbers中。

解决方案 #

修复后的完整代码 #

from pathlib import Path
import pandas as pd
import re

## OPENING FILES ##
entries = Path(r'C:\Users\jmcintosh\LIDT Project (copy)\LIDT Project\Solidworks Test (DEV)')
xlEntries = pd.read_excel(r'C:\Users\jmcintosh\LIDT Project (copy)\LIDT Project\LIDT New Webspec         Titles 2.0.xlsx')

## Variable Definitions ##
partNumbers = []
specName = []
rowNumber = []
specValue = []

# 遍历目录提取零件号，增加非空检查
for entry in entries.iterdir():
    partNumbertemp = re.findall('[0-9]+', entry.name)
    if partNumbertemp:  # 确保找到数字再添加，避免索引错误
        partNumbers.append(int(partNumbertemp[0]))

# 批量筛选所有匹配零件号的行，提升效率
matching_rows = xlEntries[xlEntries['StockNumber'].isin(partNumbers)]

# 遍历每个零件号获取对应数据
for part_num in partNumbers:
    # 获取当前零件号对应的行
    target_rows = matching_rows[matching_rows['StockNumber'] == part_num]
    if target_rows.empty:
        print(f"零件号 {part_num} 未找到匹配行")
        continue
    # 遍历匹配到的每一行，收集数据
    for idx in target_rows.index:
        rowNumber.append(int(idx))
        specName.append(target_rows.loc[idx, "Pat's Proposed Change"])
        specValue.append(target_rows.loc[idx, "StringValue"])

# 验证输出
print("rowNumber:", rowNumber)
print("specName:", specName)
print("specValue:", specValue)

关键改进点 #

• 修复行号添加逻辑：直接遍历匹配到的行号索引，逐个添加到rowNumber数组，确保每个元素是单个行号数值。
• 增加无匹配处理：检查当前零件号是否有匹配行，避免空数据导致后续错误。
• 优化代码效率：用pandas的isin和布尔索引批量筛选数据，替代循环逐个查找，提升运行速度。
• 移除冗余代码：删除无效的while ([] in partNumbers)循环，增加零件号提取时的非空检查，避免潜在错误。

内容的提问来源于stack exchange，提问作者Jaiven McIntosh