l = [1, 'a', 2, 'b']
print(type(l))
print('修改前：', l)
# 修改list的内容
l[0] = 3
print('修改后：', l)
# 末尾添加元素
l.append(4)
print('添加后：', l)
# 遍历list
print('遍历list(for循环)：')
for item in l:
print(item)
# 通过索引遍历list
print('遍历list(while循环)：')
i = 0
while i != len(l):
print(l[i])
i += 1
# 列表合并
print('列表合并(+)：', [1, 2] + [3, 4])
# 列表重复
print('列表重复(*)：', [1] * 5)
# 判断元素是否在列表中
print('判断元素存在(in)：', 1 in [1, 2])
<class 'list'>
修改前： [1, 'a', 2, 'b']
修改后： [3, 'a', 2, 'b']
添加后： [3, 'a', 2, 'b', 4]
遍历list(for循环)：
3
a
2
b
4
遍历list(while循环)：
3
a
2
b
4
列表合并(+)： [1, 2, 3, 4]
列表重复(*)： [1, 1, 1, 1, 1]
判断元素存在(in)： True
t = (1, 'a', 2, 'b')
print(type(t))
#元组的内容不能修改，否则会报错
# t[0] = 3
# 遍历tuple
print('遍历list(for循环)：')
for item in t:
print(item)
# 通过索引遍历tuple
print('遍历tuple(while循环)：')
i = 0
while i != len(t):
print(t[i])
i += 1
# 解包 unpack
a, b, c, d = t
print('unpack: ', c)
# 确保unpack接收的变量个数和tuple的长度相同，否则报错
# 经常出现在函数返回值的赋值时
# a, b, c = t
<class 'tuple'>
遍历list(for循环)：
1
a
2
b
遍历tuple(while循环)：
1
a
2
b
unpack: 2
d = {'小象学院': 'http://www.chinahadoop.cn/',
'百度': 'https://www.baidu.com/',
'阿里巴巴': 'https://www.alibaba.com/',
'腾讯': 'https://www.tencent.com/'}
print('通过key获取value: ', d['小象学院'])
# 遍历key
print('遍历key: ')
for key in d.keys():
print(key)
# 遍历value
print('遍历value: ')
for value in d.values():
print(value)
# 遍历item
print('遍历item: ')
for key, value in d.items():
print(key + ': ' + value)
# format输出格式
print('format输出格式：')
for key, value in d.items():
print('{}的网址是{}'.format(key, value))
通过key获取value: http://www.chinahadoop.cn/
遍历key:
小象学院
百度
阿里巴巴
腾讯
遍历value:
http://www.chinahadoop.cn/
https://www.baidu.com/
https://www.alibaba.com/
https://www.tencent.com/
遍历item:
小象学院: http://www.chinahadoop.cn/
百度: https://www.baidu.com/
阿里巴巴: https://www.alibaba.com/
腾讯: https://www.tencent.com/
format输出格式：
小象学院的网址是http://www.chinahadoop.cn/
百度的网址是https://www.baidu.com/
阿里巴巴的网址是https://www.alibaba.com/
腾讯的网址是https://www.tencent.com/
print('创建set:')
my_set = {1, 2, 3}
print(my_set)
my_set = set([1, 2, 3, 2])
print(my_set)
print('添加单个元素:')
my_set.add(3)
print('添加3', my_set)
my_set.add(4)
print('添加4', my_set)
print('添加多个元素：')
my_set.update([4, 5, 6])
print(my_set)
创建set:
{1, 2, 3}
{1, 2, 3}
添加单个元素:
添加3 {1, 2, 3}
添加4 {1, 2, 3, 4}
添加多个元素：
{1, 2, 3, 4, 5, 6}
# 索引获取数据
s = '数据分析'
print('索引操作：')
print('s[0]: ', s[0])
print('s[0:2]: ', s[0:2])
print('s[-1]: ', s[-1])
print('s[-2:]: ', s[-2:])
print('split分割字符串：')
s2 = 'Python is a widely used high-level programming language for general-purpose programming.'
print(s2.split(' '))
索引操作：
s[0]: 数
s[0:2]: 数据
s[-1]: 析
s[-2:]: 分析
split分割字符串：
['Python', 'is', 'a', 'widely', 'used', 'high-level', 'programming', 'language', 'for', 'general-purpose', 'programming.']
import datetime as dt
import time as tm
# 从1970年1月1日算起
print('当前时间：', tm.time())
dt_now = dt.datetime.fromtimestamp(tm.time())
print(dt_now)
print('{}年{}月{}日'.format(dt_now.year, dt_now.month, dt_now.day))
# 日期计算
delta = dt.timedelta(days=100)
print('今天的前100天：', dt.date.today() - delta)
print(dt.date.today() > dt.date.today() - delta)
当前时间： 1507787612.7655463
2017-10-12 13:53:32.766546
2017年10月12日
今天的前100天： 2017-07-04
True
class Person:
def __init__(self, name, company='自由职业'):
self.name = name
self.company = company
def set_name(self, name):
self.name = name
def set_company(self, company):
self.company= company
p = Person('小王')
print('{}的职业是{}'.format(p.name, p.company))
p.set_company('数据分析师')
p.set_name('王工')
print('{}的职业是{}'.format(p.name, p.company))
小王的职业是自由职业
王工的职业是数据分析师
import math
print('示例1，获取两个列表对应位置上的最小值：')
l1 = [1, 3, 5, 7, 9]
l2 = [2, 4, 6, 8, 10]
mins = map(min, l1, l2)
print(mins)
# map()函数操作时，直到访问数据时才会执行
for item in mins:
print(item)
print('示例2，对列表中的元素进行平方根操作：')
squared = map(math.sqrt, l2)
print(squared)
print(list(squared))
示例1，获取两个列表对应位置上的最小值：
<map object at 0x0000000005B41FD0>
1
3
5
7
9
示例2，对列表中的元素进行平方根操作：
<map object at 0x0000000005B41EB8>
[1.4142135623730951, 2.0, 2.449489742783178, 2.8284271247461903, 3.1622776601683795]
my_func = lambda a, b, c: a * b
print(my_func)
print(my_func(1, 2, 3))
# 结合map
print('lambda结合map')
l1 = [1, 3, 5, 7, 9]
l2 = [2, 4, 6, 8, 10]
result = map(lambda x, y: x * 2 + y, l1, l2)
print(list(result))
<function <lambda> at 0x0000000004544620>
2
lambda结合map
[4, 10, 16, 22, 28]
print('找出1000内的偶数(for循环)：')
l1 = []
for i in range(1000):
if i % 2 == 0:
l1.append(i)
print(l1)
找出1000内的偶数(for循环)：
[0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 62, 64, 66, 68, 70, 72, 74, 76, 78, 80, 82, 84, 86, 88, 90, 92, 94, 96, 98, 100, 102, 104, 106, 108, 110, 112, 114, 116, 118, 120, 122, 124, 126, 128, 130, 132, 134, 136, 138, 140, 142, 144, 146, 148, 150, 152, 154, 156, 158, 160, 162, 164, 166, 168, 170, 172, 174, 176, 178, 180, 182, 184, 186, 188, 190, 192, 194, 196, 198, 200, 202, 204, 206, 208, 210, 212, 214, 216, 218, 220, 222, 224, 226, 228, 230, 232, 234, 236, 238, 240, 242, 244, 246, 248, 250, 252, 254, 256, 258, 260, 262, 264, 266, 268, 270, 272, 274, 276, 278, 280, 282, 284, 286, 288, 290, 292, 294, 296, 298, 300, 302, 304, 306, 308, 310, 312, 314, 316, 318, 320, 322, 324, 326, 328, 330, 332, 334, 336, 338, 340, 342, 344, 346, 348, 350, 352, 354, 356, 358, 360, 362, 364, 366, 368, 370, 372, 374, 376, 378, 380, 382, 384, 386, 388, 390, 392, 394, 396, 398, 400, 402, 404, 406, 408, 410, 412, 414, 416, 418, 420, 422, 424, 426, 428, 430, 432, 434, 436, 438, 440, 442, 444, 446, 448, 450, 452, 454, 456, 458, 460, 462, 464, 466, 468, 470, 472, 474, 476, 478, 480, 482, 484, 486, 488, 490, 492, 494, 496, 498, 500, 502, 504, 506, 508, 510, 512, 514, 516, 518, 520, 522, 524, 526, 528, 530, 532, 534, 536, 538, 540, 542, 544, 546, 548, 550, 552, 554, 556, 558, 560, 562, 564, 566, 568, 570, 572, 574, 576, 578, 580, 582, 584, 586, 588, 590, 592, 594, 596, 598, 600, 602, 604, 606, 608, 610, 612, 614, 616, 618, 620, 622, 624, 626, 628, 630, 632, 634, 636, 638, 640, 642, 644, 646, 648, 650, 652, 654, 656, 658, 660, 662, 664, 666, 668, 670, 672, 674, 676, 678, 680, 682, 684, 686, 688, 690, 692, 694, 696, 698, 700, 702, 704, 706, 708, 710, 712, 714, 716, 718, 720, 722, 724, 726, 728, 730, 732, 734, 736, 738, 740, 742, 744, 746, 748, 750, 752, 754, 756, 758, 760, 762, 764, 766, 768, 770, 772, 774, 776, 778, 780, 782, 784, 786, 788, 790, 792, 794, 796, 798, 800, 802, 804, 806, 808, 810, 812, 814, 816, 818, 820, 822, 824, 826, 828, 830, 832, 834, 836, 838, 840, 842, 844, 846, 848, 850, 852, 854, 856, 858, 860, 862, 864, 866, 868, 870, 872, 874, 876, 878, 880, 882, 884, 886, 888, 890, 892, 894, 896, 898, 900, 902, 904, 906, 908, 910, 912, 914, 916, 918, 920, 922, 924, 926, 928, 930, 932, 934, 936, 938, 940, 942, 944, 946, 948, 950, 952, 954, 956, 958, 960, 962, 964, 966, 968, 970, 972, 974, 976, 978, 980, 982, 984, 986, 988, 990, 992, 994, 996, 998]
print('找出1000内的偶数(列表推导式)：')
l2 = [i for i in range(1000) if i % 2 == 0]
print(l2)
找出1000内的偶数(列表推导式)：
[0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 62, 64, 66, 68, 70, 72, 74, 76, 78, 80, 82, 84, 86, 88, 90, 92, 94, 96, 98, 100, 102, 104, 106, 108, 110, 112, 114, 116, 118, 120, 122, 124, 126, 128, 130, 132, 134, 136, 138, 140, 142, 144, 146, 148, 150, 152, 154, 156, 158, 160, 162, 164, 166, 168, 170, 172, 174, 176, 178, 180, 182, 184, 186, 188, 190, 192, 194, 196, 198, 200, 202, 204, 206, 208, 210, 212, 214, 216, 218, 220, 222, 224, 226, 228, 230, 232, 234, 236, 238, 240, 242, 244, 246, 248, 250, 252, 254, 256, 258, 260, 262, 264, 266, 268, 270, 272, 274, 276, 278, 280, 282, 284, 286, 288, 290, 292, 294, 296, 298, 300, 302, 304, 306, 308, 310, 312, 314, 316, 318, 320, 322, 324, 326, 328, 330, 332, 334, 336, 338, 340, 342, 344, 346, 348, 350, 352, 354, 356, 358, 360, 362, 364, 366, 368, 370, 372, 374, 376, 378, 380, 382, 384, 386, 388, 390, 392, 394, 396, 398, 400, 402, 404, 406, 408, 410, 412, 414, 416, 418, 420, 422, 424, 426, 428, 430, 432, 434, 436, 438, 440, 442, 444, 446, 448, 450, 452, 454, 456, 458, 460, 462, 464, 466, 468, 470, 472, 474, 476, 478, 480, 482, 484, 486, 488, 490, 492, 494, 496, 498, 500, 502, 504, 506, 508, 510, 512, 514, 516, 518, 520, 522, 524, 526, 528, 530, 532, 534, 536, 538, 540, 542, 544, 546, 548, 550, 552, 554, 556, 558, 560, 562, 564, 566, 568, 570, 572, 574, 576, 578, 580, 582, 584, 586, 588, 590, 592, 594, 596, 598, 600, 602, 604, 606, 608, 610, 612, 614, 616, 618, 620, 622, 624, 626, 628, 630, 632, 634, 636, 638, 640, 642, 644, 646, 648, 650, 652, 654, 656, 658, 660, 662, 664, 666, 668, 670, 672, 674, 676, 678, 680, 682, 684, 686, 688, 690, 692, 694, 696, 698, 700, 702, 704, 706, 708, 710, 712, 714, 716, 718, 720, 722, 724, 726, 728, 730, 732, 734, 736, 738, 740, 742, 744, 746, 748, 750, 752, 754, 756, 758, 760, 762, 764, 766, 768, 770, 772, 774, 776, 778, 780, 782, 784, 786, 788, 790, 792, 794, 796, 798, 800, 802, 804, 806, 808, 810, 812, 814, 816, 818, 820, 822, 824, 826, 828, 830, 832, 834, 836, 838, 840, 842, 844, 846, 848, 850, 852, 854, 856, 858, 860, 862, 864, 866, 868, 870, 872, 874, 876, 878, 880, 882, 884, 886, 888, 890, 892, 894, 896, 898, 900, 902, 904, 906, 908, 910, 912, 914, 916, 918, 920, 922, 924, 926, 928, 930, 932, 934, 936, 938, 940, 942, 944, 946, 948, 950, 952, 954, 956, 958, 960, 962, 964, 966, 968, 970, 972, 974, 976, 978, 980, 982, 984, 986, 988, 990, 992, 994, 996, 998]
import csv
with open('grades.csv') as csvfile:
grades_data = list(csv.DictReader(csvfile))
print('记录个数：', len(grades_data))
print('前2条记录：', grades_data[:2])
print('列名：', list(grades_data[0].keys()))
记录个数： 2315
前2条记录： [OrderedDict([('student_id', 'B73F2C11-70F0-E37D-8B10-1D20AFED50B1'), ('assignment1_grade', '92.73394640624123'), ('assignment1_submission', '2015-11-02 06:55:34.282000000'), ('assignment2_grade', '83.03055176561709'), ('assignment2_submission', '2015-11-09 02:22:58.938000000'), ('assignment3_grade', '67.16444141249367'), ('assignment3_submission', '2015-11-12 08:58:33.998000000'), ('assignment4_grade', '53.01155312999494'), ('assignment4_submission', '2015-11-16 01:21:24.663000000'), ('assignment5_grade', '47.710397816995446'), ('assignment5_submission', '2015-11-20 13:24:59.692000000'), ('assignment6_grade', '38.16831825359636'), ('assignment6_submission', '2015-11-22 18:31:15.934000000')]), OrderedDict([('student_id', '98A0FAE0-A19A-13D2-4BB5-CFBFD94031D1'), ('assignment1_grade', '86.79082085792986'), ('assignment1_submission', '2015-11-29 14:57:44.429000000'), ('assignment2_grade', '86.29082085792986'), ('assignment2_submission', '2015-12-06 17:41:18.449000000'), ('assignment3_grade', '69.7726566863439'), ('assignment3_submission', '2015-12-10 08:54:55.904000000'), ('assignment4_grade', '55.0981253490751'), ('assignment4_submission', '2015-12-13 17:32:30.941000000'), ('assignment5_grade', '49.5883128141676'), ('assignment5_submission', '2015-12-19 23:26:39.285000000'), ('assignment6_grade', '44.62948153275085'), ('assignment6_submission', '2015-12-21 17:07:24.275000000')])]
列名： ['student_id', 'assignment1_grade', 'assignment1_submission', 'assignment2_grade', 'assignment2_submission', 'assignment3_grade', 'assignment3_submission', 'assignment4_grade', 'assignment4_submission', 'assignment5_grade', 'assignment5_submission', 'assignment6_grade', 'assignment6_submission']
avg_assign1 = sum(float(row['assignment1_grade']) for row in grades_data) / len(grades_data)
print('assignment1平均分数：', avg_assign1)
assignment1平均分数： 74.5357320747794
assign1_sub_month = set(row['assignment1_submission'][:7] for row in grades_data)
print(assign1_sub_month)
{'2015-11', '2015-09', '2015-12', '2016-03', '2016-01', '2016-07', '2016-04', '2016-05', '2016-08', '2016-02', '2016-06', '2015-10'}