Question

这是我的原始代码，可以在Python上正常运行：

from sys import argv

script, filename = argv

print "We're going to erase %r." % filename
print "If you don't want that, hit CTRL-C (^C)."
print "If you do want that, hit RETURN."

raw_input("?")

print "Opening the file..."
target = open(filename, 'w')

print "Truncating the file.     Goodbye!"
target.truncate()

print "Now I'm going to ask you for three lines."

line1 = raw_input("line 1: ")
line2 = raw_input("line 2: ")
line3 = raw_input("line 3: ")

print "I'm going to write these to the file."

target.write("%s \n%s \n%s \n") % (line1, line2, line3)

print "And finally, we close it."
target.close()

然后我试图清理重复：

from sys import argv

script, filename = argv

print "We're going to erase %r." % filename
print "If you don't want that, hit CTRL-C (^C)."
print "If you do want that, hit RETURN."

raw_input("?")

print "Opening the file..."
target = open(filename, 'w')

print "Truncating the file.     Goodbye!"
target.truncate()

print "Now I'm going to ask you for three lines."

line1 = raw_input("line 1: ")
line2 = raw_input("line 2: ")
line3 = raw_input("line 3: ")

print "I'm going to write these to the file."

target.write("%s \n%s \n%s \n") % (line1, line2, line3)

print "And finally, we close it."
target.close()

由于某些原因，新代码没有完全运行，它会到达第27行然后返回

TypeError：％支持的操作数类型：＆＃39; NoneType＆＃39;和＆＃39; str＆＃39;

有关如何纠正此问题的任何想法？

我对编码非常陌生，我正在学习使用Zed Shaw＆＃34;艰难的学习代码＆＃34;来学习编码，所以对此有任何帮助将非常感激

Answer 1

看起来您的行target.write("%s \n%s \n%s \n") % (line1, line2, line3)就是问题所在。

在进行变量替换之前，您已关闭write函数调用。因此变量line1，line2和line3没有被插入％s＆＃39; s。因此，您有一堆None正在写入而导致错误。

将其更改为：

target.write("%s \n%s \n%s \n" % (line1, line2, line3))

Answer 2

%是一个字符串运算符;您正尝试将其与target.write()的返回值一起使用。

target.write("%s \n%s \n%s \n" % (line1, line2, line3))

如果您刚刚开始，我建议您切换到Python 3.5和str.format语法。这样，你就不会有过早关闭括号的问题：

target.write("{0} \n{1} \n{2} \n".format(line1, line2, line3))

3.6版本目前正在开发并开始进行beta测试，它将有一种更自然的语法来构建这种名为f strings的字符串：

target.write(f'{line1}\n{line2}\n{line3}\n')

遇到TypeError

2 个答案: