运行 python 中的程序时如何跳过我的 .txt 文件中的空行

Question

我正在编写一个程序，该程序从文本文件中读取和提取数据，然后对数据进行一些计算。

但是，由于我的文本文件中有空格，检索数字时出错。我得到

ValueError: invalid literal for int() with base10: ' '

我的文本文件看起来像这样：

['flower', 'sdfsd', '21/08/2019 20:27:03', 1]

['hello', 'sdsdfsdf', '21/08/2019 20:27:36', '2']

['car', 'sdfsd', '21/08/2019 20:27:45', 1]

['table', 'sdfsdf', '21/08/2019 20:29:21', 1]

_(blank space \n)_

['shirt', 'sdfsdf', '21/08/2019 20:30:02', '2']

_(blank space \n)_

['hello', 'sdfsdf', '21/08/2019 20:30:07', '3']

我从 python 写入文本文件的代码如下所示：

historyFile = open('history.txt','a')
historyFile.write("\n\r")
historyFile.write(file)
historyFile.close()

我已经在网上试过像if not line.strip():这样的例子，但是它在空行后停止检索数据

以下是我的代码：

readFile = open('history.txt','r')
searching = readFile.readlines()
i=0
for line in searching:
    if i in range(len(searching)-1):
        i += 1
        oldCount = str(int(searching[i].split(",")[3][-4]))
        newCount = str(int(searching[i].split(",")[3][-4]) + 1)
        print("\nold count: " + oldCount + " new count: " + newCount)

它应该运行通过我的文本文件中的所有行和 return 我列表中第 3 位的数字，但是由于空行，我得到了错误

Answer 1

for line in searching:
    if line != '\n': # check if line not '\n'
        if i in range(len(searching)-1):
                  ....

Answer 2

如果您的 history.txt 包含（注意空白行）：

flower, 'sdfsd', '21/08/2019 20:27:03', 1
hello, 'sdsdfsdf', '21/08/2019 20:27:36', 2
car, 'sdfsd', '21/08/2019 20:27:45', 1
table, 'sdfsdf', '21/08/2019 20:29:21', 1

shirt, 'sdfsdf', '21/08/2019 20:30:02', 2

hello, 'sdfsdf', '21/08/2019 20:30:07', 3

然后此脚本将读取文件并打印最后一列增加 1：

with open('history.txt', 'r') as readFile:
    for i, line in enumerate(readFile, 1):
        line = line.strip()
        if not line:
            continue

        line_tuple = tuple(map(str.strip, line.split(',')))

        oldCount = int(line_tuple[3])
        newCount = oldCount + 1
        print("row no. {} old count: {} new count: {}".format(i, oldCount, newCount))

打印：

row no. 1 old count: 1 new count: 2
row no. 2 old count: 2 new count: 3
row no. 3 old count: 1 new count: 2
row no. 4 old count: 1 new count: 2
row no. 6 old count: 2 new count: 3
row no. 8 old count: 3 new count: 4

编辑：如果您的 history.txt 包含带引号的字段：

'flower','sdfsd','21/08/2019 20:27:03','1'
'hello','sdsdfsdf','21/08/2019 20:27:36','2'
'car','sdfsd','21/08/2019 20:27:45','1'
'table','sdfsdf','21/08/2019 20:29:21','1'

'shirt','sdfsdf','21/08/2019 20:30:02','2'

'hello','sdfsdf','21/08/2019 20:30:07','3'

可以使用csv模块阅读：

import csv

with open('history.txt', 'r') as readFile:
    csvreader = csv.reader(readFile, delimiter=',', quotechar="'")

    for i, line in enumerate(csvreader, 1):
        if not line:
            continue

        oldCount = int(line[3])
        newCount = oldCount + 1
        print("row no. {} old count: {} new count: {}".format(i, oldCount, newCount))

运行 python 中的程序时如何跳过我的 .txt 文件中的空行

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