函數(shù)

細節(jié)

1. import 文件名 可以導(dǎo)入自己的文件調(diào)用其中的模塊，如函數(shù)

import caculate
res = caculate.caculateNum(100)
print(res)

輸出

image.png

2. 列表推導(dǎo)式實現(xiàn)一行輸出

def caculateNum(num):
    # res = 0
    # for i in range(1, num+1):
    #     res += i
    # return res
    return sum([i for i in range(1, num+1)])

3. 必須參數(shù)和關(guān)鍵字參數(shù)

#必須參數(shù)和關(guān)鍵字參數(shù)


def f(name, age):
    print('I am %s , I am %d'%(name, age))
    

#關(guān)鍵字參數(shù),此時允許函數(shù)調(diào)用和聲明時順序不一樣
f(age=18, name='eric')

4. 默認參數(shù)

#默認參數(shù) 缺省參數(shù)沒有傳入，默認值會生效

def f(name, age, sex = 'male'):
    print('I am %s , I am %d'%(name, age))
    print('Sex%s'%sex)
    
    
f(name='lisi', age=19)
f('張三', 88, 'female')
#是否顯示指定參數(shù)：方便自己閱讀為目的

輸出

image.png

5. 匿名函數(shù)
   和條件判斷式一起使用更加

# 匿名函數(shù)
# 語法 ：
# lambda 參數(shù): 表達式
#冒號前面是參數(shù)，可以有多個，冒號后面時表達式
#只能有一個，不寫return 返回值是表達式的結(jié)果
#減少代碼量，‘優(yōu)雅


def rect(x, y):
    return x * y


area = rect(3, 5)
print(area)


#使用lambda表達式
res = lambda x, y: x*y
print(res(4, 5))
store = []
s = "dangdangziying" if len(store) == 0 else store[0]
print(s)
def cal(x, y):
    if x>y:
        return x*y
    else:
        return x/y


calc = lambda x, y: x*y if x > y else x/y
print(calc(5, 4))
calc = lambda x, y: x*y if x > y else x/y
print(calc(2, 4))

輸出

image.png

在列表排序中的使用

#列表排序中使用
stus = [
    {'name': 'zhangsan', 'age': 33},
    {'name': 'lisi', 'age': 12},
    {'name': 'wangwu', 'age': 53},
    {'name': 'zhaoliu', 'age': 18},
    {'name': 'tianqi', 'age': 77}
]
print(stus)
#key值按照哪個元素為依據(jù)排序
res = sorted(stus, key=lambda x: x['age'], reverse=True)
print('排序后', res)

res = sorted(stus, key=lambda x: x['name'], reverse=True)
print('排序后', res)

輸出

image.png

6. 綜合案例
   三國中人物出現(xiàn)的次數(shù)
   用wordcloud生成詞云圖片

# 案例三國小說人物出場頻率統(tǒng)計
import jieba
from collections import Counter
from wordcloud import WordCloud

def parse():
    # 定義無關(guān)詞集合
    excludes = {"將軍", "卻說", "丞相", "二人", "不可", "荊州", "不能", "如此", "商議",
                "如何", "主公", "軍士", "軍馬", "左右", "次日", "引兵", "大喜", "天下",
                "東吳", "于是", "今日", "不敢", "魏兵", "陛下", "都督", "人馬", "不知",
                '玄德曰', '孔明曰', '劉備', '關(guān)公'
                }
    """三國小說人物出場頻率統(tǒng)計"""
    with open('threekingdom.txt', 'r', encoding='utf-8') as f:
        txt = f.read()
    # print(txt)
    words = jieba.lcut(txt)
    print(words)
    # 鍵是名字
    counts = {}
    for word in words:
        if len(word) == 1:
            continue
        else:
            # 向字典中增加元素 缺省值為0
            counts[word] = counts.get(word, 0)+1
    print(counts)

    # 統(tǒng)計標準
    counts['孔明'] = counts.get('孔明') + counts.get('孔明曰')
    counts['玄德'] = counts.get('玄德曰') + counts.get('玄德')
    counts['玄德'] = counts.get('玄德') + counts.get('劉備')
    counts['關(guān)公'] = counts.get('關(guān)公') + counts.get('云長')


    for word in excludes:
        del counts[word]

    # 統(tǒng)計出現(xiàn)頻次最高的前20個詞
    items = list(counts.items())
    # print(items)
    items.sort(key=lambda x: x[1], reverse=True)
    # print('排序后', items)
    for i in range(20):
        character, count = items[i]
        print(character, count)

    #方法2
    roles = Counter(counts)
    role = roles.most_common(10)
    print(role)


    # 構(gòu)造詞云字符串
    li = []
    for i in range(10):
        character, count = items[i]
        for _ in range(count):
            li.append(character)
    print(li)
    cloud_txt = ",".join(li)

    wc = WordCloud(
        background_color='while',
        font_path='msyh.ttc',
        # 是否包含兩個詞的搭配，莫熱門true
        collocations=False
    ).generate(cloud_txt)
    wc.to_file('三國詞云.png')

parse()

# jieba分詞
txt = '我來到北京清華大學(xué)'
# 將字符串分割成等量中文
seg_list = jieba.lcut(txt)
print(seg_list)

輸出

image.png

這里得包不好導(dǎo)，在自己得電腦中
pip install xxxxx
然后file-setting-project-interpreter 然后右上角加號導(dǎo)入包到項目中