python 如何在逗号分隔的字符串中用零替换空字符串？
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How to replace empty string with zero in comma-separated string?
提问by Kev
"8,5,,1,4,7,,,,7,,1,9,3,6,,,8,6,3,9,,2,5,4,,,,,3,2,,,7,4,1,1,,4,,6,9,,5,,,,5,,,1,,6,3,,,6,5,,,,7,4,,1,7,6,,,,8,,5,,,7,1,,3,9,"
"8,5,,1,4,7,,,,7,,1,9,3,6,,,8,6,3,9,,2,5,4,,,,,3,2 ,,,7,4,1,1,,4,,6,9,,5,,,,5,,,1,,6,3,,,6,5,,,,7,4,, 1,7,6,,,,,8,,5,,,7,1,,3,9,"
I'm doing a programming challenge where i need to parse this sequence into my sudoku script. Need to get the above sequence into 8,5,0,1,4,7,0,0,0,7,0,1,9,3,6,0,0,8......... I tried re but without success, help is appreciated, thanks.
我正在做一个编程挑战，我需要将此序列解析为我的数独脚本。需要把上面的序列变成8,5,0,1,4,7,0,0,0,7,0,1,9,3,6,0,0,8........ . 我试过重新但没有成功，感谢帮助，谢谢。
回答by unutbu
You could use
你可以用
[(int(x) if x else 0) for x in data.split(',')]
data.split(',')splits the string into a list. It splits on the comma character:
data.split(',')将字符串拆分为一个列表。它在逗号字符上拆分：
['8', '5', '', '1', '4', '7', '', '', '', ...]
The expression
表达方式
(int(x) if x else 0)
returns int(x)if xis True, 0 if xis False. Note that the empty string is False.
int(x)如果x为真则返回，如果x为假则返回0 。请注意，空字符串为 False。
回答by Dietrich Epp
Regular expressions are often unnecessary in Python. Given string s, try:
Python 中通常不需要正则表达式。给定 string s，尝试：
','.join(x or '0' for x in s.split(','))
I am assuming you want to fill the blanks with 0. If you want a list of integers instead of a string, try this:
我假设你想用 0 填充空格。如果你想要一个整数列表而不是一个字符串，试试这个：
[(x and int(x)) or 0 for x in s.split(',')]
回答by Joachim Sauer
s = "8,5,,1,4,7,,,,7,,1,9,3,6,,,8,6,3,9,,2,5,4,,,,,3,2,,,7,4,1,1,,4,,6,9,,5,,,,5,,,1,,6,3,,,6,5,,,,7,4,,1,7,6,,,,8,,5,,,7,1,,3,9,"
s = re.sub('((?<=,)|^)(?=,|$)', '0', s)
print s
Prints:
印刷：
8,5,0,1,4,7,0,0,0,7,0,1,9,3,6,0,0,8,6,3,9,0,2,5,4,0,0,0,0,3,2,0,0,7,4,1,1,0,4,0,6,9,0,5,0,0,0,5,0,0,1,0,6,3,0,0,6,5,0,0,0,7,4,0,1,7,6,0,0,0,8,0,5,0,0,7,1,0,3,9,0
8,5,0,1,4,7,0,0,0,7,0,1,9,3,6,0,0,8,6,3,9,0,2,5,4,0,0,0,0,3,2,0,0,7,4,1,1,0,4,0,6,9,0,5,0,0,0,5,0,0,1,0,6,3,0,0,6,5,0,0,0,7,4,0,1,7,6,0,0,0,8,0,5,0,0,7,1,0,3,9,0
回答by John La Rooy
Simplest I can think of is
我能想到的最简单的是
[int(x or 0) for x in s.split(',')]
or
或者
[int('0'+x) for x in s.split(',')]
回答by mellort
My solution uses map,lambda, and split. The final code looks like this:
我的解决方案使用map，lambda和split。最终代码如下所示：
sudoku_string = "1,2,3,,4,5,,6"
output_string = map(lambda x: '0' if x=='' else x, sudoku_string.split(","))
If you want the output as a list (i.e. [1,2,3,0,4,5,0,6]), then use
如果您希望将输出作为列表（即[1,2,3,0,4,5,0,6]），则使用
output_list = map(lambda x: 0 if x=='' else int(x), sudoku_string.split(",")
The commands mapand lambdaare very useful. maptakes in a function and a list (really an iterable, but that's another story), and applies the function to every element of this list. So
命令map和lambda非常有用。map接受一个函数和一个列表（实际上是一个可迭代的，但那是另一回事），并将该函数应用于该列表的每个元素。所以
def plus_one(x):
return x+1
map(plus_one, [1,2,3,4])
returns [2,3,4,5]. lambdais a way to quickly define functions, so we can write plus_oneas
返回[2,3,4,5]。lambda是一种能够快速定义功能，让我们可以写plus_one为
lambda x: x+1
Lastly, splittakes a string and creates a list by 'splitting' the string by the argument you pass. So "1 2 3 4".split(" ")yields [1,2,3,4].
最后，split接受一个字符串并通过您传递的参数“拆分”字符串来创建一个列表。所以"1 2 3 4".split(" ")产量[1,2,3,4]。
回答by ghostdog74
>>> s="8,5,,1,4,7,,,,7,,1,9,3,6,,,8,6,3,9,,2,5,4,,,,,3,2,,,7,4,1,1,,4,,6,9,,5,,,,5,,,1,,6,3,,,6,5,,,,7,4,,1,7,6,,,,8,,5,,,7,1,,3,9,"
>>> s=s.split(",")
>>> for n,i in enumerate(s):
... if i=="" : s[n]=0
...
>>> s
['8', '5', 0, '1', '4', '7', 0, 0, 0, '7', 0, '1', '9', '3', '6', 0, 0, '8', '6', '3', '9', 0, '2', '5', '4', 0, 0, 0, 0, '3', '2', 0, 0, '7', '4', '1', '1', 0, '4', 0, '6', '9', 0, '5', 0, 0, 0, '5', 0, 0, '1', 0, '6', '3', 0, 0, '6', '5', 0, 0, 0, '7', '4', 0, '1', '7', '6', 0, 0, 0, '8', 0, '5', 0, 0, '7', '1', 0, '3', '9', 0]
>>>
