在python中跳过范围函数中的值

Question

循环一系列数字并跳过一个值的Python式方法是什么？例如，范围是从 0 到 100，我想跳过 50。

编辑： 这是我正在使用的代码

for i in range(0, len(list)):
    x= listRow(list, i)
    for j in range (#0 to len(list) not including x#)
        ...

Answer 1

您可以使用其中任何一个：

# Create a range that does not contain 50
for i in [x for x in xrange(100) if x != 50]:
    print i

# Create 2 ranges [0,49] and [51, 100] (Python 2)
for i in range(50) + range(51, 100):
    print i

# Create a iterator and skip 50
xr = iter(xrange(100))
for i in xr:
    print i
    if i == 49:
        next(xr)

# Simply continue in the loop if the number is 50
for i in range(100):
    if i == 50:
        continue
    print i

Answer 2

除了 Python 2 方法之外，这里还有 Python 3 的等效方法：

# Create a range that does not contain 50
for i in [x for x in range(100) if x != 50]:
    print(i)

# Create 2 ranges [0,49] and [51, 100]
from itertools import chain
concatenated = chain(range(50), range(51, 100))
for i in concatenated:
    print(i)

# Create a iterator and skip 50
xr = iter(range(100))
for i in xr:
    print(i)
    if i == 49:
        next(xr)

# Simply continue in the loop if the number is 50
for i in range(100):
    if i == 50:
        continue
    print(i)

范围在 Python 2 中是列表，在 Python 3 中是迭代器。

Answer 3

如果跳过值的索引已知，则无需比较每个数字：

import itertools

m, n = 5, 10
for i in itertools.chain(range(m), range(m + 1, n)):
    print(i)  # skips m = 5

顺便说一句，即使它有效，你也不想使用

(*range(m), *range(m + 1, n))

，因为它会将可迭代对象扩展为一个元组，而这会导致内存效率低下。

---

来源：njzk2 的评论

Answer 4

for i in range(0, 101):
if i != 50:
    do sth
else:
    pass

Answer 5

for i in range(100):
    if i == 50:
        continue
    dosomething

Answer 6

这取决于你想做什么。例如，您可以在您的理解中加入一些像这样的条件：

# get the squares of each number from 1 to 9, excluding 2
myList = [i**2 for i in range(10) if i != 2]
print(myList)

# --> [0, 1, 9, 16, 25, 36, 49, 64, 81]

Answer 7

这对我有用；

示例：

x = ['apple', 'orange', 'grape', 'lion', 'banana', 'watermelon', 'onion', 'cat',]

for xr in x:
    if xr in 'onion':
        print('onion is a vegetable')
        continue
    if (xr not in 'lion' and xr not in 'cat'):
        print(xr, 'is a fruit')

输出-->

apple is a fruit
orange is a fruit
grape is a fruit
banana is a fruit
watermelon is a fruit
onion is a vegetable

Answer 8

如果您想跳过初始数字可能未知的连续数字，最好使用

while

循环。

# Loop through a range of numbers from 0 to 100 and skip over number 50 as well
# as the next 3 consecutive numbers (51, 52, 53). Additionally, skip over 11 to 14.

i = 0
initial_skip_num = (50, 11, )
while i < 100:
    if i in initial_skip_num:
        i += 4
    print(i)
    i += 1

输出：

0
1
...
9
10
15
16
...
48
49
54
55
...

如果要跳过的初始数字未知或需要跳过多个连续数字，这会很有帮助

Answer 9

您可以使用set.difference：

   list(set.difference(                                                                                                                                              
       set(range(0, 32)),                                                                                                                                         
       set((0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 13, 15, 20, 21))))

结果：

Out[37]: [11, 14, 16, 17, 18, 19, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31]

Answer 10

你可以做的就是在循环内的所有你想要远离 50 的内容周围放置一个 if 语句。 例如

for i in range(0, len(list)):
    if i != 50:
        x= listRow(list, i)
        for j in range (#0 to len(list) not including x#)