Python学习基础笔记——modules（模块操作）

modules(模块)

1.引入模块，例如

math

模块

import math
root=math.sqrt(36)
flr=math.floor(89.9)
print(root)
print(flr)
6.0
89.0

2.给模块的名字赋予简称，之后都可以使用简称

import math as m
root=m.sqrt(64)
print(root)
8.0

3.模块中包含许多函数，只引用其中一个或两个

from math import sqrt
root=sqrt(49)
print(root)
7.0

from math import *

4.提取模块中的一个变量

import math
print(math.pi)
3.141592653589793

5.打开和读取csv文件，将文件内容变换为list类型

import csv
f=open("nfl.csv")
csvraeder=csv.reader(f)
nfl=list(csvreader)

[['2009', '1', 'Pittsburgh Steelers', 'Tennessee Titans'],
['2009', '1', 'Minnesota Vikings', 'Cleveland Browns'],
['2009', '1', 'New York Giants', 'Washington Redskins'],
['2009', '1', 'San Francisco 49ers', 'Arizona Cardinals'],
['2009', '1', 'Seattle Seahawks', 'St. Louis Rams'],
['2009', '1', 'Philadelphia Eagles', 'Carolina Panthers'],
['2009', '1', 'New York Jets', 'Houston Texans'],
['2009', '1', 'Atlanta Falcons', 'Miami Dolphins'],
['2009', '1', 'Baltimore Ravens', 'Kansas City Chiefs'],
['2009', '1', 'Indianapolis Colts', 'Jacksonville Jaguars'],
['2009', '1', 'New Orleans Saints', 'Detroit Lions'],

6.读取list列表中的信息

import csv
f=open("nfl.csv")
csvreader=csv.reader(f)
nfl=list(csvreader)
patriots_wins=0
for row in nfl:
if row[2]=="New England Patriots":
patriots_wins+=1

61

7.自定义函数

import csv
f = open("nfl.csv", 'r')
nfl = list(csv.reader(f))

# Define your function here.
def nfl_wins(team):
count=0
for row in nfl:
if row[2]==team:
count=count+1
return count
cowboys_wins=nfl_wins("Dallas Cowboys")
falcons_wins=nfl_wins("Atlanta Falcons")