Python基本练习三(字符统计与列表解析训练)

一时失言乱红尘 2022-02-19 08:51 164阅读 0赞

### 文章目录 ###

*  Python基本练习三
 *   *  猴子吃桃问题。
     *  杨辉三角
     *  统计重复数字
     *  统计数字
     *  重复数统计
     *  字符串重复统计
 *  列表解析训练
 *   *  打印九九乘法表
     *   *   *   *  生成ID
 *  函数训练
 *   *  矩阵翻转
     *  翻转不规则矩阵

# Python基本练习三 #

## 猴子吃桃问题。 ##

猴子第一天摘下若干个套装，当即吃了一半，还不过瘾,又多吃了一个。第二天早上又将剩下的桃子吃掉一半，又多吃了一个。以后每天找事都吃了前一天剩下的一半零一个。到第10天找事想吃时，只剩下一个桃子了，求第一天共摘多少个桃子

num = 1 #第10天剩下1个桃子
    for i in range(9,0,-1):
        num = (num+1)*2
        print("第{}天有{}个".format(i,num))
    print(num)

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTMwMDg3OTU_size_16_color_FFFFFF_t_70]

## 杨辉三角 ##

\#求杨辉三角第m行的第k个元素，  
\#1.第m行有m项，m是正整数，因此k一定不会大于m  
\#2.第n行的m个元素可表示为C(n-1,m-1),即为从n-1个不通元素中取m-1个元素的组合数

n = int(input("请输入要打印的行数："))
    arr = [1]*(n+1)
    nn = n//2 if n&1 else n//2 +1
    for i in range(1,nn+1):
        num1 = 1
        num2 = 1
        for k in range(1,i+1):
            num1 *=(n-k+1)
            num2 *= k
        num3 = int(num1/num2)
        arr[i]= num3
        arr[-i-1]= num3
    print(arr);

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTMwMDg3OTU_size_16_color_FFFFFF_t_70 1]

## 统计重复数字 ##

\#随机产生10个数，每个数字取值范围是\[1,20\],统计重复的数字有几个？分别是什么？不重复的数字有几个？分别是什么

*  第一种解法

import random
    str1 = []
    str2 = []
    for i in range(10):
        num = random.randint(1,20) 
        if num in str2:
            continue
        if num in str1:
            str2.append(str1.pop(str1.index(num)))
        else:
            str1.append(num)
    print("有{}个数重复，分别是：{}".format(len(str2),str2))
    print("有{}个数没有重复过，分别是：{}".format(len(str1),str1))

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTMwMDg3OTU_size_16_color_FFFFFF_t_70 2]

*  第二种解法

#第二种解法
    n = 20
    num = [ random.randint(1,20) for _ in range(n)]
    numindex = [0]*n
    retetition = [] #二维数组，重复的数字和次数
    noretetition = []  #不重复的数字
    for i in range(len(num)):
        if numindex[i] != 0: continue
        count = 0
        for k in range(i+1,len(num)):
            if numindex[i] != 0: continue
            if num[k] == num[i]:
                numindex[k] = 1
                count +=1
        if count:
            retetition.append([num[i],count+1])
        else:
            noretetition.append(num[i])
    print(num)
    print("重复：",retetition)
    print("不重复：",noretetition)

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTMwMDg3OTU_size_16_color_FFFFFF_t_70 3]

## 统计数字 ##

\#\#第一题 用户输入数字统计  
\#用户输入一个数字，打印每一位数字及其重复的次数

import random
    #arr = [ random.randint(0,9) for _ in range(20)]
    arr = [int(input("请输入一个数字")) for _ in range(10)]
    #arr = [1,2,3,5,1,2]
    countdict = { };
    for i in arr:
        countdict[i] = countdict.setdefault(i,0) + 1
    for k,v in countdict.items():
        print("{}出现了{}次".format(k,v))
    print(countdict)

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTMwMDg3OTU_size_16_color_FFFFFF_t_70 4]

## 重复数统计 ##

\#随机产生100个整数，数字范围\[-1000,1000\]升序输出这些数字并打印其重复的次数

####第一种思路，排序后统计
    import random
    from collections import OrderedDict
    arr = [random.randint(-1000,1000) for _ in range(100)]
    arr.sort()
    odict = OrderedDict()
    for i in range(len(arr)):
        odict[arr[i]] = odict.setdefault(arr[i],0)+1
        if i+1<len(arr) and arr[i]!=arr[i+1]:
            print("{}出现了{}次".format(arr[i],odict[arr[i]]))
    print("{}出现了{}次".format(arr[-1],odict[arr[-1]]))
    #print(arr,odict,sep="\n")
    
    #####第二种思路，统计后，排序keys,然后输出
    import random
    #arr = [1,2,3,5,4,2,3,1]
    arr = [random.randint(-1000,1000) for _ in range(100)]
    countdict = { }
    for i in arr:
        countdict[i] = countdict.setdefault(i,0) + 1
    countkey = list(countdict.keys())
    countkey.sort()
    for i in countkey:
        print("{}出现了{}次".format(i,countdict[i]))
    #print(arr,countdict,countkey,sep="\n")

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTMwMDg3OTU_size_16_color_FFFFFF_t_70 5]

## 字符串重复统计 ##

\#\#第三题 字符串重复统计 字符表’a~z’随机挑选2个字母组成字符串，共挑选100次，降序输出这100个字符串及重复的次数

import random,string
    arr = [ "".join(random.choices(string.ascii_lowercase,k=2)) for _ in range(100)]
    countdict = { }
    for i in arr:
        countdict[i] = countdict.setdefault(i,0)+1
    sortkey = list(countdict.keys())
    sortkey.sort()
    for i in sortkey:
        print("{}出现了{}次".format(i,countdict[i]))

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTMwMDg3OTU_size_16_color_FFFFFF_t_70 6]

# 列表解析训练 #

## 打印九九乘法表 ##

#打印九九乘法表
    arr = [ print("{}*{}={}".format(k,i,i*k),end= "\n" if i==k else "\t") for i in range(1,10) for k in range(1,i+1)]

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTMwMDg3OTU_size_16_color_FFFFFF_t_70 7]

##### 生成ID #####

\#\#"0001.abadicddws"是Id格式，要求ID格式是以点号分割，左边是4位从1开始的整数，右边是10位随机小写英文字母。请依次生成前100个Id的列表

["{:0>4}.{}".format(i,bytes(random.choices(range(97,123),k=10)).decode()) for i in range(1,101)]

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTMwMDg3OTU_size_16_color_FFFFFF_t_70 8]

# 函数训练 #

## 矩阵翻转 ##

#矩阵转换
    
    #显示矩阵
    def showMatrix(arr):
       for i in arr:
           print("\t".join([str(_) for _ in i]))
    
    #创建矩阵
    def getMatrix(n):
       arr = [[0]*n for _ in range(n)]
       count = 1
       for i in arr:
           for k in range(len(i)):
               i[k] = count
               count += 1
       return arr
    
    #翻转矩阵
    def overMatrix(arr):
       for i in range(len(arr)):
           for k in range(0,i):
               arr[i][k],arr[k][i] = arr[k][i],arr[i][k] 
       return arr
    
    #调用
    arr = getMatrix(5)
    showMatrix(arr)
    print("--------------")
    showMatrix(overMatrix(arr))

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTMwMDg3OTU_size_16_color_FFFFFF_t_70 9]

## 翻转不规则矩阵 ##

#翻转不规则矩阵
    ##创建矩阵
    def getMatrix(x,y):
        arr = [[0]*x for _ in range(y)]
        count = 1
        for i in arr:
            for k in range(len(i)):
                i[k] = count
                count += 1
        return arr 
    
    #显示矩阵
    def showMatrix(arr):
        for i in arr:
            print("\t".join([str(_) for _ in i]))
    #翻转矩阵
    def overMatrix(arr):
        x = len(arr[0])
        y = len(arr)
        arr1 = [[0]*y for _ in range(x)]
        for i in range(len(arr1)):
            for k in range(len(arr1[i])):
                arr1[i][k] = arr[k][i]
        return arr1
    
    #直接翻转显示矩阵
    def showOverMatrix(arr):
        for i in range(len(arr[0])):
            for k in range(len(arr)):
                print(arr[k][i],end="\t")
            print("")
    
    arr = getMatrix(5,2)
    showMatrix(arr)
    print("------")
    showOverMatrix(arr)
    #showMatrix(overMatrix(arr))

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTMwMDg3OTU_size_16_color_FFFFFF_t_70 10]

*  第二种方法

matrix = [[1,2,3],[4,5,6]]
    tm = []
    
    for i,row in enumerate(matrix):
        for k,col in enumerate(row):
    # if i==0: #
    # tm.append([])
            if len(tm) < k +1:
                tm.append([])
            tm[k].append(col)
    # print(col,sep="",end="")
    # print("")
    print(*tm,sep="\n")

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTMwMDg3OTU_size_16_color_FFFFFF_t_70 11]

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