002---Python基本資料型別--字串
摘要：
字串的定義與建立
定義：字串是一個有序的字元集合，用來儲存和表示文字資訊。用雙引和單引表示。是一種不可變型別。
In [9]:
s = 'Hello Python'
print(s)
Hello Python...
字串的定義與建立
定義：字串是一個有序的字元集合，用來儲存和表示文字資訊。用雙引和單引表示。是一種不可變型別。
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s = 'Hello Python' print(s)
Hello Python
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# 索引和切片 s = 'Python' print(s[1])# y print(s[-1])# n print(s[1:4]) # yth顧頭不顧尾
y n yth
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# capitalize()首字母大寫 s = 'hello python' print(s.capitalize())# Hello python
Hello python
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# upper()lower()全大寫和全小寫 s1 = 'hello python' s2 = 'HELLO PYTHON' print(s1.upper())# Hello python print(s2.lower())# hello python
HELLO PYTHON hello python
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# title()每個隔開(特殊字元和數字)的單詞的首字母大寫 s = 'life is short you need python' print(s.title())# Life Is Short You Need Python
Life Is Short You Need Python
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# center()兩邊按指定字元填充居中 s = 'python' print(s.center(20,'-'))# -------python-------
-------python-------
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#len()長度字元數 s = 'i love you jiang zi ya' print(len(s))# 22 s1 = '我喜歡你' print(len(s1)) # 4
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# startswith()判斷是否以什麼什麼開頭支援指定起始和終止
s = 'jiang ziya'
print(s.startswith('jiang'))# True
print(s.startswith('ziya'))# False
print(s.startswith('jiang',0,5)) # True
print(s.startswith('jiang',0,4)) # False
True False True False
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# find()查詢每個字元的索引沒找到返回-1支援指定起始和終止
s = 'jiang zi ya'
print(s.find('z'))
print(s.find('zi'))
print(s.find('Jiang'))
6 6 -1
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# index()查詢每個字元的索引沒找到報錯
print(s.index('z'))
print(s.index('zi'))
# print(s.index('Jiang'))
---------------------------------------------------------------------------
ValueErrorTraceback (most recent call last)
<ipython-input-20-ff6187789150> in <module>
2 print(s.index('z'))
3 print(s.index('zi'))
----> 4print(s.index('Jiang'))
ValueError: substring not found
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# strip()去除兩邊的指定字串預設刪空格rstrip() 左邊lstrip()右邊
s = 'python'
print(s.strip())
print(s.strip(''))
print(s.strip(' '))
print(''.center(20,'-'))
s1 = '*%jiang*%wei*%%%%'
print(s1.strip('*%'))
python python python -------------------- jiang*%wei
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# count() 計算某個字元的個數 支援指定起始和終止位置
s = 'Python python'
print(s.count('t'))
print(s.count('jiang'))
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# split()按照指定字元切割預設按照空格切割返回列表
s = ' i love you '
print(s.split())
print(s.split(' '))
s1 = '--he--he--he--'
print(s1.split('--'))
['i', 'love', 'you'] ['', 'i', 'love', 'you', ''] [' i love you '] ['', 'he', 'he', 'he', '']
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# replace() 替換 可以指定替換數
s = 'who are you who are you who are you'
print(s.replace('you','she'))
print(s.replace('you','she',2))
who are she who are she who are she who are she who are she who are you
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# is系列 name = 'jiangziya1' print(name.isalpha())# 判斷字串是否由字母組成 print(name.isalnum())# 判斷字串是否由數字和字母組成 print(name.isdigit())# 判斷字串是否右數字組成
False True False