名单*名单 [英] list*list

问题描述

必须有更好的方法将一个列表的元素乘以

另一个：


a = [1,2,3]
b = [1,2,3]

c = []

for i in range（len（a））：

c.append（a [i] * b [i]）

a = c

打印a

[1,4,9]


也许列表理解还是由NumPy更好地解决？


谢谢，


jab

There must be a better way to multiply the elements of one list by
another:

a = [1,2,3]
b = [1,2,3]
c = []
for i in range(len(a)):
c.append(a[i]*b[i])
a = c
print a
[1, 4, 9]

Perhaps a list comprehension or is this better addressed by NumPy?

Thanks,

jab

推荐答案

>必须有一种更好的方法将一个列表的元素乘以

> There must be a better way to multiply the elements of one list by

另一个：

a = [1,2,3]
b = [1， 2,3]
c = []
我在范围内（len（a））：
c.append（a [i] * b [i]）
a = c
打印
[1,4,9]

或许是列表理解还是由NumPy更好地解决？

another:

a = [1,2,3]
b = [1,2,3]
c = []
for i in range(len(a)):
c.append(a[i]*b[i])
a = c
print a
[1, 4, 9]

Perhaps a list comprehension or is this better addressed by NumPy?

首先：如果您想要的是一个

枚举的索引，那么使用范围被认为是不好的风格，因为它实际上会创建一个大小的列表

指定。在这种情况下使用xrange。


你可以使用这样的listcomp：


c = [a [i] * b [i] for我在xrange（len（a））]


但也许更好的是拉链：


c = [av * bv for av，bv in zip（a，b）]


如果列表变大且可能是多维的，numpy当然是

的方式。


Diez

First of all: it''s considered bad style to use range if all you want is a
enumeration of indices, as it will actually create a list of the size you
specified. Use xrange in such cases.

You can use a listcomp like this:

c = [a[i] * b[i] for i in xrange(len(a))]

But maybe nicer is zip:

c = [av * bv for av, bv in zip(a, b)]

And if lists get large and perhaps multidemnsional, numpy certainly is the
way to go.

Diez

>必须有一种更好的方法将一个列表的元素乘以

> There must be a better way to multiply the elements of one list by

另一个：

a = [1,2,3]
b = [1， 2,3]
c = []
我在范围内（len（a））：
c.append（a [i] * b [i]）
a = c
打印
[1,4,9]

或许列表理解还是由NumPy更好地解决？

another:

a = [1,2,3]
b = [1,2,3]
c = []
for i in range(len(a)):
c.append(a[i]*b[i])
a = c
print a
[1, 4, 9]

Perhaps a list comprehension or is this better addressed by NumPy?

a = [1,2,3]

b = [1,2,3]

c = [q * r表示q，r表示拉链（a） ，b）]


似乎对我有用。


-tim

a = [1,2,3]
b = [1,2,3]
c = [q*r for q,r in zip(a,b)]

seems to do the trick for me.

-tim

" Diez B. Roggisch" <德*** @ nospam.web.de>在消息中写道

新闻：4b ************* @ uni-berlin.de ...

"Diez B. Roggisch" <de***@nospam.web.de> wrote in message
news:4b*************@uni-berlin.de...

它被认为是坏的如果你想要的只是一个索引的枚举，因为它实际上会创建一个你指定的大小的列表。在这种情况下使用xrange。

it''s considered bad style to use range if all you want is a
enumeration of indices, as it will actually create a list of the size you
specified. Use xrange in such cases.

我很确定这种区别在2.5中消失了。

干杯，

Alan Isaac

I''m pretty sure this distinction goes away in 2.5.
Cheers,
Alan Isaac

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