12

我是 Python 新手，正在尝试处理一些示例脚本。我正在做一个简单的收银机类型的事情，但我想证明或右对齐输出，使其看起来像这样：

subTotal = 24.95
tax = subTotal * 0.0725
total = subTotal + tax
paid = 30
change = paid-total
print("The subtotal was: $",subTotal)
print("The tax was: $",tax)
print("The total was: $",total)
print("The customer paid: $",paid)
print("Change due: $",change)

我知道我可以用更少的打印语句来简化它，但我只是想让它更容易看到我想要做什么。

我希望它输出类似这样的内容，请注意美元金额都是对齐的，并且 $ 和美元金额之间没有空格。我不知道如何做这两件事。

The subtotal was:   $24.95
The tax was:         $1.81
The total was:      $26.76
The customer paid:  $30.00
Change due:          $3.24

我尝试阅读有关格式方法的 Python 文档，但我没有看到任何关于可以使用哪些格式说明符来执行某些操作的示例。提前感谢您的帮助。

4

5 回答 5

10

金额可以这样形成：

"${:.2f}".format(amount)

您可以为字符串添加填充，例如宽度为 20：

"{:20s}".format(mystring)

您可以右对齐字符串，例如宽度为 7：

"{:>7s}".format(mystring)

把所有这些放在一起：

s = "The subtotal was:"
a = 24.95
print("{:20s}{:>7s}".format(s, "${.2f}".format(a))
于 2013-04-23T01:26:41.350 回答
4

如果您知道文本和数字的最大大小，您可以这样做

val_str = '${:.2f}'.format(val)
print('{:<18} {:>6}'.format(name+':', val_str))

如果事先不知道这些，就会变得更加棘手。这是一种方法，假设names和values是列表：

value_format = '${:.2f}'.format
name_format = '{}:'.format
values_fmt = [value_format(val) for val in values]
names_fmt = [name_format(name) for name in names]
max_value_len = max(len(x) for x in values_fmt)
max_name_len = max(len(x) for x in names_fmt)
for name, val in zip(names_fmt, values_fmt):
    print('{:<{namelen}} {:>{vallen}}'.format(name, val,
        namelen=max_name_len, vallen=max_value_len))
于 2013-04-23T01:26:20.870 回答
4 
subTotal = 24.95
tax = subTotal * 0.0725
total = subTotal + tax 
paid = 30
change = paid-total

text  = [ 
"The subtotal was:", "The tax was:", "The total was:",
"The customer paid:", "Change due:"
]
value = [ subTotal, tax, total, paid, change ]

for t,v in zip(text, value):
    print "{0:<25} ${1:.2f}".format(t, v)

输出

The subtotal was:         $24.95
The tax was:              $1.81
The total was:            $26.76
The customer paid:        $30.00
Change due:               $3.24

您还可以像这样获得所需的间距：

maxLen = max(len(t) for t in text)  
for t,v in zip(text, value):
    print str("{0:<" + str(maxLen) + "} ${1:.2f}").format(t, v)
于 2013-04-23T01:31:47.783 回答
2

见http://docs.python.org/2/library/string.html#grammar-token-width

def myformat(name, value):
    return "{:<18} {:>6}".format(name, "${:.2f}".format(value))
print(myformat("The subtotal was:", subTotal))
print(myformat("The tax was:", tax))
print(myformat("The total was:", total))
print(myformat("The customer paid:", paid))
print(myformat("Change due:", change))

输出：

The subtotal was:  $24.95
The tax was:        $1.81
The total was:     $26.76
The customer paid: $30.00
Change due:         $3.24
于 2013-04-23T01:33:11.633 回答
1 
subTotal = 24.95
tax = subTotal * 0.0725
total = subTotal + tax
paid = 30
change = paid-total
print("The subtotal was: %8s" % ("$%.2f" % subTotal))
print("The tax was:      %8s" % ("$%.2f" % tax))
print("The total was:    %8s" % ("$%.2f" % total))
print("The customer paid:%8s" % ("$%.2f" % paid))
print("Change due:       %8s" % ("$%.2f" % change))
于 2013-04-23T01:43:25.293 回答