[英]Replacing items in a two dimensional list in python
I am trying to append the second item in my two dimensional. 我想在我的二维中附加第二个项目。 I have tried a few dozen different ways and can't seem to get it to append. 我已经尝试了几十种不同的方式,似乎无法让它追加。
def main():
values = [[10,0], [13, 0], [36, 0], [74,0], [22,0]]
user = int(input('Enter a whole number'))
for i in range(len(values)):
print(values[i])
(current out put) (当前输出)
10, 0
13, 0
36, 0
74, 0
22, 0
(were the second part it is values[0] + user input) (第二部分是值[0] +用户输入)
[10, 12]
[13, 15]
[36, 38]
[74, 76]
[22, 24]
with list comprehension 列表理解
user = 2
[[x[0], sum(x)+user] for x in values]
>>> [[10, 12], [13, 15], [36, 38], [74, 76], [22, 24]]
or using map: 或使用地图:
map(lambda x: [x[0], sum(x)+user], values)
First, you can nearly always avoid iterating over range(len(iterable))
- in this case, your loop can be written as the much nicer: 首先,您几乎总能避免迭代range(len(iterable))
- 在这种情况下,您的循环可以写得更好:
for value in values:
print(value)
for exactly the same functionality. 完全相同的功能。
I'm not sure from your description exactly how you want the code to behave, but it seems like you want something like this - each line of output will have the first item of the corresponding value
, and then that added to the user input; 我不确定你的描述究竟是你想要代码的行为,但似乎你想要这样的东西 - 每行输出都会有相应value
的第一项,然后添加到用户输入中; ie, ignoring the second item of the existing input entirely: 即完全忽略现有输入的第二项:
for value in values:
total = value[0] + user
print((value[0], total))
or if you want it to overwrite the second item of each value
for later use in your program: 或者如果您希望它覆盖每个value
的第二项以供以后在您的程序中使用:
values = [[10,0], [13, 0], [36, 0], [74,0], [22,0]]
for value in values:
value[1] = value[0] + user
print(value)
Shouldn't it be just like this? 不应该这样吗?
>>> def f():
values = [[10,0], [13, 0], [36, 0], [74,0], [22,0]]
user = int(input('Enter a whole number'))
for i in range(len(values)):
values[i][1]=values[i][0]+user
print(values[i])
>>> f()
Enter a whole number2
[10, 12]
[13, 15]
[36, 38]
[74, 76]
[22, 24]
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