146 lines
2.4 KiB
Markdown
146 lines
2.4 KiB
Markdown
---
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title: String字符串的内建函数
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date: 2020-07-21 22:27:31
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tags: [Python]
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categories: [Python]
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author: Anges黎梦
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---
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## String的内建函数
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`示例字符串`
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```
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var = " abcdefghijklmn黎梦 "
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```
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### capitalize()
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> 将字符串的第一个字母转换为大写
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```
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print(var.capitalize())
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```
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### count()
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> 统计字符串中某一个字符出现的次数，
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```
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print(var.count("b"))
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print(var.count("b"[0:7])) # 在index范围内，查找某一个字符出现的次数
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```
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### endswith()
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> 是判断，字符串是否以xxx结束，返回布尔值
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```
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print(var.endswith("n"))
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```
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### find()
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> 检测字符串是否包含某个字符，若是，则返回index，若不是，则返回-1
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```
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print(var.find('g'))
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```
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### index()
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> 返回字符在字符串中的index值，若不存在字符串中，则抛出异常
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```
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print(var.index('c'))
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```
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### isalnum()
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> 如果字符串至少有一个字符并且所有字符都是字母或者数字，则返回True，否则返回False
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```
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print(var.isalnum())
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```
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### isalpha()
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> 如果字符串至少有一个字符，并且所有字符都是字母或者中文字则返回True
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```
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print(var.isalpha())
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```
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### isdigit()
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> 判断字符串是否只包含数字
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```
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print(var.isdigit())
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```
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### islower()
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> 判断字符串中包含至少一个区分大小写的字符，并且这些字符都是小写则返回True
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```
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print(var.islower())
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```
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### isupper()
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> 判断字符串中包含至少一个区分大小写的字符，并且这些字符都是大写则返回True
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```
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print(var.isupper())
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```
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### lower()
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> 转换字符串所有字符为小写
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```
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print(var.lower())
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```
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### swapcase()
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> 转换字符串所有字符 小写转换为大写，大写转换为小写
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```
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print(var.swapcase())
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```
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### upper()
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> 转换字符串所有字符为大写
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```
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print(var.upper())
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```
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### len()
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> 长度
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```
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print(len(var))
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```
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### join
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```
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print(",".join(["a","b","ccc"]))
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```
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### replace
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```
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print(var.replace("a", "Q"))
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```
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### lstrip()
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> 清除左边的空格或者指定字符
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```
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print(var.lstrip())
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```
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### rstrip()
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> 清除右边的空格或者指定字符
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```
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print(var.rstrip())
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```
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### split()
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> 截取，分割
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```
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print(var.split("j"))
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```
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### startswith()
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> 是否以xxx开头
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```
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print(var.startswith(' '))
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```
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### 字符串翻转
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```
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print(var[::-1])
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print(reversed(var))
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print(''.join(reversed(var)))
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```
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### sorted()
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> 字符串排序
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```
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print(sorted(var))
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```
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