[python]python學習筆記part3

posted in: C/C++程式設計 | 0

input:
name = input(“請輸入你的名稱:”)

print: =>print(value, …, sep=’ ‘, end=’\n’, file=sys.stdout)
print(1, 2, 3, sep=”,”, end=”\n\n”) #以,作為分隔,結束時多空2行

print(1, 2, 3, file = open(“data.txt”, “w”)) #將資料寫入data.txt

open回傳_io.TextIOWrapper物件

格式化字串:

text = “%d %.2f %s” % (10, 0.3, “test”)

int(“1″) =>形態轉換

open:
open(file,mode=”r”,buffering=None,encoding=None,
errors=None,newline=None,closefd=True)

如下:
file = open(name, ‘r’, encoding=’UTF-8′)

使用方法:
content = file.read() =>一次讀入所有檔案
print(content)
file.close()

while True:
line = file.readline()
if not line: break
print(line, end=”)

name = input(‘請輸入檔名:’)
file = open(name, ‘r’, encoding=’UTF-8′)
for line in file.readlines(): #一次全讀進來陣列之後再跑迴圈,效率比較不好
print(line, end=”)
file.close()

name = input(‘請輸入檔名:’)
for line in open(name, ‘r’, encoding=’UTF-8′): #檔案會自動關閉
print(line, end=”)

寫檔方法:
name = input(‘請輸入檔名:’)
file = open(name, ‘w’, encoding = ‘UTF-8’)
file.write(‘test’)
file.close()

0b10 =>8進位
0x10 =>16進位

type(1) =>查看型態

oct(10)=>8進位
hex(10)=>16進位

int(’10’, 8) =>指定成8進位

10 // 3 =3 =>去小數

2 ** 100 =>2^100 次方運算

>>> 1.0 – 0.8
0.19999999999999996 =>使用repr()函式來顯示=>程式開發人員該了解的結果
>>> print(1.0 – 0.8)
0.2 =>使用str()函式來顯示較友善、適於非開發人員觀看的結果

>>> import decimal #用來顯示浮點數精確的結果
>>> a = decimal.Decimal(‘1.0’)
>>> b = decimal.Decimal(‘0.8’)
>>> a – b
Decimal(‘0.2’)

複數的寫法:
>>> a = 3 + 2j
>>> b = 5 + 3j
>>> c = a + b
>>> c
(8+5j)
>>> type(c)
< class 'complex'

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