some codes

最近有个小需求，需要对指定层数的目录进行遍历查找

import os
def SearchAbsPath(root_path):
    root_depth = len(root_path.split(os.path.sep))
    c, d = [], []
    for root, dirs, files in os.walk(root_path, topdown=True):
        for name in dirs:
            dir_path = os.path.join(root, name)
            dir_depth = len(dir_path.split(os.path.sep))
            if dir_depth == root_depth + 1
                c.append(dir_path)
            elif dir_depth == root_depth + 2:
                d.append(dir_path)
            else: break
    return c, d

打印进度条

# 方式一
import time
for i in range(0, 101, 2):
    time.sleep(0.1)
    char_num = i // 2
    per_str = '\r%s%% : %s\n' % (i, '*', * char_num) if i == 100 else '\r%s%% : %s' % (i, '*', * char_num)
    print(per_str, end='', flush=True)
# 方式二
from tqdm import tqdm
import time

for i in tqdm(range(10)):
    time.sleep(1)

列表嵌套展开

lst =[1,[2],[[3]],[[4,[5],6]],7,8,[9]]
def flat(nums):
    res = []
    for i in nums:
        if isinstance(i, list):
            res.extend(flat(i))
        else:
            res.append(i)
    return res

new_lst = flat(lst)
print(new_lst)`

参考资料

字典互换键值对

三种方式交换键值对（前提：值唯一）：
1.
mydict={"a":1,"b":2,"c":3}
mydict_new={}
for key,val in mydict.items():
    mydict_new[val]=key

2.
mydict={"a":1,"b":2,"c":3}
mydict_new=dict([val,key] for key,val in mydict.items())

3.利用zip运算符：
mydict={"a":1,"b":2,"c":3}
mydict_new=dict(zip(mydict.values(),mydict.keys()))

参考资料
lambda

twosum

class Solution(object):
    def twoSum(self, nums, target):
        result = []
        for i in range(0,len(nums)):
            oneNum = nums[i]
            twoNum  = target - oneNum
            if twoNum in nums:
                j = nums.index(twoNum)
                if i != j:
                    result.append(i)
                    result.append(j)
                    return result`

twosum