{:02d} 在 Python 中是什么意思
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what does {:02d} mean in Python
提问by lxdthriller
it's very hard to find information about {:}online
I saw some code below:
很难在{:}网上找到有关信息我在下面看到了一些代码：
def dateformat(date):
day, month, year=date.split('/')
return "{:4d}{:02d}{:02d}".format(int(year),int(month),int(day))
I kinda of know it is filling leading 0in the format, but I don't know what do '02'and 'd'in {:02d}do?
我还挺知道它是填补领先0的格式，但我不知道该怎么做'02'，并'd'在{:02d}做什么？
回答by Martijn Pieters
You are looking for the str.format()documentation. Specifically, the 02dpart is documented in the Format Specification Mini-Language.
您正在查找str.format()文档。具体来说，该02d部分记录在Format Specification Mini-Language 中。
02dformats an integer (d) to a field of minimum width 2 (2), with zero-padding on the left (leading 0):
02d将整数 ( d)格式化为最小宽度为 2 ( 2)的字段，左侧填充零（前导0）：
>>> 'No digits: {:02d}, 1 digit: {:02d}, 2: {:02d}, 3: {:02d}'.format(0, 7, 42, 151)
'No digits: 00, 1 digit: 07, 2: 42, 3: 151'
From the documentation:
从文档：
format_spec ::= [[fill]align][sign][#][0][width][,][.precision][type][...]
widthis a decimal integer defining the minimum field width.
When no explicit alignment is given, preceding the widthfield by a zero (
'0') character enables sign-aware zero-padding for numeric types. This is equivalent to a fill character of'0'with an alignment type of'='.[...]
Finally, the typedetermines how the data should be presented. [...]The available integer presentation types are:
[...]
'd'
Decimal Integer. Outputs the number in base 10.
format_spec ::= [[fill]align][sign][#][0][width][,][.precision][type][...]
width是定义最小字段宽度的十进制整数。
当没有给出明确的对齐方式时，在宽度字段前面加上一个零 (
'0') 字符为数字类型启用符号感知零填充。这相当于'0'对齐类型为 的填充字符'='。[...]
最后，类型决定了数据的呈现方式。[...]可用的整数表示类型有：
[...]
'd'
十进制整数。输出以 10 为底的数字。
