python - personal tips

Posted 2020-09-20

这两天放假在家，拿py重写了之前的统计脚本，算是好好practice了一把各种基本用法，记录一下，为了将来的加速。。

 

• 判断命令行参数，给出Usage提示

if len(sys.argv) != 3:
    print("Usage: %s <folder name> <12 or 24>" % sys.argv[0])
    sys.exit(1)

• float 设置小数点位数

datatable[row][27] = round(float(ServerUtilDict[server]["avgUser"])/100, 4)  # 用round函数控制位数

• 字典basic

遍历　

ServerUtilDict, UtilDict = {}, {}
for (k, v) in FolderIPDict.items():
    UtilDict = copy.deepcopy(UtilDict) if UtilDict else UtilDict
    UtilDict = {}
    ServerUtilDict[v] = UtilDict    

# 以上，字典嵌套字典，利用FolderIPDict中的v作为ServerUtilDict中的k，对应的v为UtilDict，注意要deepcopy，不然指向同一个引用

字典构造

PowerDict = {}  # Dict一定要先初始化
PowerDict["avg"] = line.split(" ")[0].strip() # 直接指定key赋值，对比list，要用append函数添加

字典引用

ServerPerfDict[server]["sql_nbr"] # 外层dict的v是另外一个dict，直接用内层dict的k来做引用
# sample

In [278]: util={}

In [279]: util["avg"] = 10

In [280]: util["max"] = 12

In [281]: util
Out[281]: {‘avg‘: 10, ‘max‘: 12}

In [283]: serverUtil = {}

In [284]: serverUtil["1.1.1.1"] = util

In [285]: serverUtil
Out[285]: {‘1.1.1.1‘: {‘avg‘: 10, ‘max‘: 12}}

In [286]: serverUtil["1.1.1.1"]["avg"]
Out[286]: 10

In [287]: serverUtil["1.1.1.1"]["max"]
Out[287]: 12

• 一维列表，初始化，引用

In [293]: utilList = [] # 必须先要初始化

In [295]: utilList.append(13) # 往列表加东西，必须要append

In [296]: utilList.append(15)

In [297]: utilList
Out[297]: [13, 15]

In [298]: serverUtil["2.2.2.2"]=utilList # 把列表作为dict某个k的v

In [299]: serverUtil
Out[299]: {‘1.1.1.1‘: {‘avg‘: 10, ‘max‘: 12}, ‘2.2.2.2‘: [13, 15]}

In [300]: serverUtil["2.2.2.2"][1] # 这样引用
Out[300]: 15

• 一维列表可以简单变二维甚至更多

In [307]: utilList
Out[307]: [13, 15]
In [308]: li=[1,2]
In [309]: li
Out[309]: [1, 2]
In [310]: li[0]
Out[310]: 1
In [311]: utilList.append(li)
In [312]: util
util      utilList
In [312]: utilList
Out[312]: [13, 15, [1, 2]]
In [313]: utilList[2]
Out[313]: [1, 2]
In [314]: utilList[2][0]
Out[314]: 1
In [315]: utilList[2][1]
Out[315]: 2

• 删除列表元素

In [316]: utilList
Out[316]: [13, 15, [1, 2]]

In [317]: del utilList[1]

In [318]: utilList
Out[318]: [13, [1, 2]]

In [319]: del utilList[1][0]

In [320]: utilList
Out[320]: [13, [2]]

• python调用bash命令

cmd_getcpu = "grep -A 1 avg-cpu " + sdr + " | grep -v ‘avg-cpu‘ | grep -v ‘\-\-‘ "                                                       "| awk -F ‘ ‘ ‘{print($1,$2,$3,$4,$5,$6)}‘ > tmpcpu"
os.system(cmd_getcpu) # create file "tmpcpu" in curent dir

#后面该怎处理怎么处理

• 　　遍历某个目录下面的子目录中的指定文件，用正则表达式匹配行，取出关键字

def getFolderIPDict(WorkingDir):
    subfolders = os.walk(WorkingDir).next()[1] # check os.walk? to understand the return tuple structure
    IPList = []
    for i, value in enumerate(subfolders):
        try:
            if value.index("tdw") == 0:
               IPList.append((value.replace("-", ".")).replace("tdw.", ""))
        except ValueError:
            print "Something wrong with sub-folders names, should be in such format: tdw-100-76-29-3"
            sys.exit(1)
            # if goes here, means "twd" not found in some of the sub-folder, probably structure wrong

    FolderIPDict = dict(zip(subfolders, IPList))
    return FolderIPDict

　　

def getServerPerfDict(FolderIPDict):
    ServerPerfFile = "sum_cron*"
    ServerPerfDict, PerfDict = {}, {}
    for (k, v) in FolderIPDict.items():
        PerfDict = copy.deepcopy(PerfDict) if PerfDict else PerfDict
        PerfDict = {}
        ServerPerfDict[v] = PerfDict
        with open(glob.glob(os.path.join(WorkingDir, k, ServerPerfFile))[0]) as f:
            # f like ../0524-24H/tdw-100-76-29-2/sum_cron.2017-05-24.tdw-100-76-29-2
            # only the 1st 10 lines in this file matters,,, could add "failure tasks info" later
            count = 0
            for line in f:
                count += 1
                if count == 3 and re.compile("Total executors mr").search(line):
                    PerfDict["mr_nbr"] = line.split(":")[1].strip()
                    continue

    # print ServerPerfDict
    # sys.exit(1)

    return ServerPerfDict