name = "lzl" def f1(): print(name) def f2(): name = 'eric' f1() f2()
('hello') *3 [_ for _ in range(0,1,0.1)]
写出一个python脚本,统计文本中包含“python” 的行数(文件可能比内存大)。 num = 0 with open('a.txt', 'r', encoding='utf8') as f: for i in f.readline(): if 'python' in i: num += 1
或者:
with open('a.txt', 'r', encoding='utf8') as f:
for i in f:
if 'python' in i:
num += 1
python打开文件后,在进行读取内容时分三种情况:
(1)read() 读取整个文件,通常将文件内容放到一个字符串变量中;
(2)readline() 每次读取一行内容;
(3)readlines() 一次性读取所有内容并按行返回list;
# 截止到报错之前a,b的值是什么, 考察浅拷贝的知识 from copy import copy def method(array): array.append(10) array[0] = 4 array[1].append(6) array[2].append(8) array[3]['qt'] = 11 if __name__ == "__main__": a = [1,[2,3],(4,5,6),{'qt':10}] b = copy(a) method(b) print(a) print(b)
def append_list(num, list_num=[]): print(list_num) for i in range(num): list_num.append(i*i) print(list_num) append_list(2) append_list(3,[3,2,1]) append_list(3) append_list(7) append_list(4, [11,12,12])
qt = ['q','i', 'n','g','teng'] num = [1,2,3,4,5] print(zip(qt,num)) a0 = dict(zip(qt,num)) print(a0) a1 = range(8) print(a1) print([i+1 for i in a1 if i in a0]) a3 = [a0[s] for s in a0] print(a3) print([i+2 for i in a1 if i in a3]) print([i*j for i in a1 if i%2 if i> 3 for j in a0])
将test中的年月份识别出来: >> ['2018年', '9月', '27日'] test = r'2018年的下半年,9月份, 不确定是不是27日'
comp = re.compile('d+(?:.d+)?(?:年|月|日)') print(comp.findall(test))