Python 基础知识点
2018年07月15日
string
1name = "li qiang" 2name.title() => "Li Qiang" 3name.upper() 4name.lower() 5 6name.strip() 7name.rstrip() 8name.lstrip()
number
1# number to string 2age = 23 3str(age) => "23" 4 5int('23') => 23
list
1a = [1, 2, 3] 2a.append(4) 3 4a.insert(0, 0) 5 6del a[0] 7 8b = a.pop() 9b = a.pop(0) 10 11# 删除值 12a.remove(3) 13 14a.sort() 15a.sort(reverse=True) 16 17b = sorted(a) 18b = sorted(a, reverse=True) 19 20a.reverse() 21 22len(a) 23 24 25for i in a: 26 print(i) 27 28for i in range(1, 5): 29 print(i) 30 31a = list(range(10)) 32 33max(a) 34min(a) 35sum(a) 36 37# 列表解析 38b = [i*2 for i in a] 39 40# 切片 41b = a[0:3] 42b = a[:3] 43b = a[2:] 44b = a[-3:] 45# 复制列表 46b = a[:] 47 48# 集合 49set(a)
元组
1a = (100, 50)
字典
1a = { 'name': 'lq', 'age': 24 } 2a['name'] 3a['age'] 4 5del a['age'] 6 7for key, value in a.items(): 8 print(key, value) 9 10for key in a: 11 print(key) 12 13for key in a.keys(): 14 print(key) 15 16for value in a.values(): 17 print(value)
用户输入
1msg = input('please input something')
function
1# 接受任意数量的参数 2# args 元组 3def func(*args): 4 for i in args: 5 print(i) 6 7# 关键词实参 8def build_profile(first, last, **user_info): 9 do something 10 11**user_info 字典
file
1# read 2with open('1.txt') as x: 3 contents = x.read() 4 print(contents) 5 6# read line 7with open('1.txt') as x: 8 for line in x: 9 print(line) 10 11# write 12with open('1.txt', 'w') as x: 13 x.write('hello world\n') 14 15# json dump 16import json 17a = [1, 2, 3] 18while open('1.txt', 'w') as x: 19 json.dump(a, x) 20 21# json load 22import json 23while open('1.txt') as x: 24 c = json.load(x)