通过在带有空格的字符串中添加双引号将值写入python中的文件答案

【问题标题】：Write values to a file in python by adding double quotes to the string with spaces通过在带有空格的字符串中添加双引号将值写入python中的文件
【发布时间】：2017-10-16 06:39:20
【问题描述】：

我正在尝试以特定方式将以下列表的值写入 txt 文件中

valList = ['1','Age',' Address has spaces','employee','98363','hobbies has space in it ']

sample.txt

1,Age,"Address has spaces",employee,98363,"hobbies has space in it "

这里如果你看到 valList 是一个异构列表，我唯一的意图是写其中有空格的值用双引号括起来，其余所有值都应该按原样写。到目前为止，我已经尝试过：

valList = ['1','Age',' Address has spaces','employee','98363','hobbies has space in it ']
# Output = 1,Age,"Address has spaces",employee,98363,"hobbies has space in it "
valstr = ",".join(valList)
with open('sample.txt','wb') as file:
    file.write(valstr)
    file.write('\n' + " \"" + valList[2] + "\" ")

使用 file.write('\n' + " \"" + valList[2] + "\" ") 行我可以用引号写入单个值，但我需要一种通用的方法来为给定的列表写入带有空格的值。

任何帮助将不胜感激。

【问题讨论】：

标签： python file file-format

【解决方案1】：

您有 CSV 数据。使用csv module，它会在需要时自动使用引用：

import csv
valList = ['1', 'Age', ' Address has spaces', 'employee', '98363', 'hobbies has space in it ']
with open('sample.txt', 'wb') as file:
    writer = csv.writer(file)
    writer.writerow(valList)

这将根据需要引用值；例如，当字段值中有逗号或换行符时。这不太符合您的确切要求，但兼容的 CSV 阅读器将能够在读取时再次从文件中获取完全相同的值。

如果您必须在带有空格的列上加上引号，您可以禁用自动引用并手动添加引号：

import csv
valList = ['1','Age',' Address has spaces','employee','98363','hobbies has space in it ']
with open('sample.txt', 'wb') as file:
    writer = csv.writer(file, quoting=csv.QUOTE_NONE, quotechar='')
    writer.writerow(['"{}"'.format(v) if ' ' in v else v for v in valList])

列表推导式用双引号将值中的空格括起来。请注意，由于我们在此处禁用了引用，因此 csv.writer() 将拒绝其中包含 逗号或换行符的值，因为它现在无法引用它们。

两种方法的演示：

>>> import sys
>>> import csv
>>> valList = ['1', 'Age', ' Address has spaces', 'employee', '98363', 'hobbies has space in it ']
>>> writer = csv.writer(sys.stdout)
>>> writer.writerow(valList)
1,Age, Address has spaces,employee,98363,hobbies has space in it
>>> writer = csv.writer(sys.stdout, quoting=csv.QUOTE_NONE, quotechar='')
>>> writer.writerow(['"{}"'.format(v) if ' ' in v else v for v in valList])
1,Age," Address has spaces",employee,98363,"hobbies has space in it "

【讨论】：

感谢 Martijn 的回复，但不幸的是，第一个答案只有在字符串中有逗号时才有效，而第二个解决方案有错误 '_csv.Error: sequence expected' 。请您再检查一次，
@csharpcoder：我更新了第二个选项以使用列表解析，我忘记了 Python 2 CSV 编写器不喜欢迭代器。
在第二个解决方案中仍然出现错误：_csv.Error: need to escape, but no escapechar set
@csharpcoder：啊，是的，我们也禁用转义字符。等一下。
谢谢第二个答案就像魅力一样，但为什么要对我的问题投反对票？

【解决方案2】：

valList = ['1','Age',' Address has spaces','employee','98363','hobbies has space in it ']

file = open('sample.txt', 'w')
for item in valList:
    if ' ' in item:
        file.write('"%s",' % item)
    else:
        file.write("%s," % item)

输出

1,Age," Address has spaces",employee,98363,"hobbies has space in it ",

【讨论】：