[英]Saving output of a function to a text file
I have a function that takes the items in multiple lists and permutates them. 我有一个函数,可以将多个列表中的项目合并在一起。 So if I have the lists
child0 = ['a', 'b']
and child1 = ['c', 'd']
: 因此,如果我有列表
child0 = ['a', 'b']
和child1 = ['c', 'd']
:
def permutate():
for i in child0:
for k in child1:
print (i, k)
permutate()
# a c
# a d
# b c
# b d
I'm running into problems with saving the output into a text file. 将输出保存到文本文件时遇到问题。 I can't assign a var to the print statement because the output will change every time it runs through obviously, and writing the permutate() function to a text file does nothing.
我无法将var分配给print语句,因为输出每次明显运行时都会改变,并且将permutate()函数写入文本文件不会执行任何操作。 Doing a return instead of print won't run the permutation properly.... any tips on how to print all the permutations to a text file properly?
用return代替print不能正确运行排列。...有关如何将所有排列正确打印到文本文件的任何提示?
You need to build a list and return that list object: 您需要构建一个列表并返回该列表对象:
def permutate():
result = []
for i in child0:
for k in child1:
result.append((i, k))
return result
for pair in permutate():
print(*pair)
What you are doing is creating the cartesian product , not the permutations. 您正在做的是创建笛卡尔乘积 ,而不是排列。
The Python standard library has a function to do just this already, in itertools.product()
: Python标准库在
itertools.product()
已经具有执行此操作的功能:
from itertools import product
list(product(child0, child1))
would produce the exact same list: 会产生完全相同的列表:
>>> from itertools import product
>>> child0 = ['a', 'b']
>>> child1 = ['c', 'd']
>>> for pair in product(child0, child1):
... print(*pair)
...
a c
a d
b c
b d
Pass a file object as an argument, and use file
argument of print
function. 传递文件对象作为参数,并使用
print
函数的file
参数。
def permutate(f):
for i in child0:
for k in child1:
print(i, k, file=f)
with open('testfile.txt', 'w') as f:
permutate(f)
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.