> For the complete documentation index, see [llms.txt](https://zeliang-yao.gitbook.io/my-note-zeliang-yao/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://zeliang-yao.gitbook.io/my-note-zeliang-yao/useful/untitled-2.md).

# String

有关字符串的常用方法:

### Split and format <a href="#split-and-format" id="split-and-format"></a>

```python
latitude = '37.24N'
longitude = '-115.81W'
'Coordinates {0},{1}'.format(latitude,longitude)
>>>   'Coordinates 37.24N,-115.81W'
```

```python
f'Coordinates {latitude},{longitude}'
>>>'Coordinates 37.24N,-115.81W'
```

```python
'{0},{1},{2}'.format(*('abc'))
>>>'a,b,c'
```

```python
coord = {"latitude":latitude,"longitude":longitude}
'Coordinates {latitude},{longitude}'.format(**coord)
>>>'Coordinates 37.24N,-115.81W'
```

### **Access argument’s attribute** <a href="#access-argument-s-attribute" id="access-argument-s-attribute"></a>

```python
class Point:
    def __init__(self,x,y):
        self.x,self.y = x,y
    def __str__(self):
        return 'Point({self.x},{self.y})'.format(self = self)
    def __repr__(self):
        return f'Point({self.x},{self.y})'
```

```python
test_point = Point(4,2)
test_point
>>>    Point(4,2)
```

```python
str(Point(4,2))
>>>'Point(4,2)'
```

### **Replace with %s , %r**  <a href="#replace-with-s-r" id="replace-with-s-r"></a>

```python
" repr() shows the quote {!r}, while str() doesn't:{!s} ".format('a1','a2')
>>> " repr() shows the quote 'a1', while str() doesn't:a2 "

```

### **Align**  <a href="#align" id="align"></a>

```python
'{:<30}'.format('left aligned')
>>>'left aligned                  '
```

```python
'{:>30}'.format('right aligned')
>>>'                 right aligned'
```

```python
'{:^30}'.format('centerd')
>>>'           centerd            '
```

```python
'{:*^30}'.format('centerd')
>>>'***********centerd************'
```

### **Replace with %x , %o**  <a href="#replace-with-x-o" id="replace-with-x-o"></a>

```python
"int:{0:d}, hex:{0:x}, oct:{0:o}, bin:{0:b}".format(42)
>>>'int:42, hex:2a, oct:52, bin:101010'
```

```python
'{:,}'.format(12345677)
>>>'12,345,677'
```

### **Percentage**  <a href="#percentage" id="percentage"></a>

```python
points = 19
total = 22
'Correct answers: {:.2%}'.format(points/total)
>>>'Correct answers: 86.36%'
```

### **Date**  <a href="#date" id="date"></a>

```python
import datetime as dt
f"{dt.datetime.now():%Y-%m-%d}"
>>>'2019-03-27'
```

```python
f"{dt.datetime.now():%d_%m_%Y}"
>>>'27_03_2019'
```

```python
today = dt.datetime.today().strftime("%d_%m_%Y")
today

'27_03_2019'
```

### **Split without parameters**  <a href="#split-without-parameters" id="split-without-parameters"></a>

```python
"this is a  test".split()
>>>['this', 'is', 'a', 'test']
```

### **Concatenate** : <a href="#concatenate" id="concatenate"></a>

```python
'do'*2
>>>'dodo'
```

```python
orig_string ='Hello'
orig_string+',World'
>>>'Hello,World'
```

```python
full_sentence = orig_string+',World'
full_sentence
>>>'Hello,World'
```

### **Check string type, slice，count，strip** : <a href="#check-string-type-slice-count-strip" id="check-string-type-slice-count-strip"></a>

```python
strings = ['do','re','mi']
', '.join(strings)
>>>'do, re, mi'
```

```python
'z' not in 'abc'
>>> True
```

```python
ord('a'), ord('#')
>>> (97, 35)
```

```python
chr(97)
>>>'a'
```

```python
s = "foodbar"
s[2:5]
>>>'odb'
```

```python
s[:4] + s[4:]
>>>'foodbar'
```

```python
s[:4] + s[4:] == s
>>>True
```

```python
t=s[:]
id(s)
>>>1547542895336
```

```python
id(t)
>>>1547542895336
```

```python
s is t
>>>True
```

```python
s[0:6:2]
>>>'fob'
```

```python
s[5:0:-2]
>>>'ado'
```

```python
s = 'tomorrow is monday'
reverse_s = s[::-1]
reverse_s
>>>'yadnom si worromot'
```

```python
s.capitalize()
>>>'Tomorrow is monday'
```

```python
s.upper()
>>>'TOMORROW IS MONDAY'
```

```python
s.title()
>>>'Tomorrow Is Monday'
```

```
s.count('o')
>>> 4
```

```python
"foobar".startswith('foo')
>>>True
```

```python
"foobar".endswith('ar')
>>>True
```

```python
"foobar".endswith('oob',0,4)
>>>True
```

```python
"foobar".endswith('oob',2,4)
>>>False
```

```python
"My name is yo, I work at xx".find('yo')
>>>11
```

```python
"My name is ya, I work at Gener".find('gent')
>>>-1
```

```python
"abc123".isalnum()
>>>True
```

```python
"abc%123".isalnum()
>>>False
```

```python
"abcABC".isalpha()
>>>True
```

```python
"abcABC1".isalpha()
>>>False
```

```python
'123'.isdigit()
>>>True
```

```python
'123abc'.isdigit()
>>>False
```

```python
'abc'.islower()
>>>True
```

```python
"This Is A Title".istitle()
>>>True
```

```python
"This is a title".istitle()
>>>False
```

```python
'ABC'.isupper()
>>>True
```

```python
'ABC1%'.isupper()
>>>True
```

```python
'foo'.center(10)
>>>'   foo    '
```

```python
'   foo bar baz    '.strip()
>>>'foo bar baz'
```

```python
'   foo bar baz    '.lstrip()
>>>'foo bar baz    '
```

```python
'   foo bar baz    '.rstrip()
>>>'   foo bar baz'
```

```python
"foo abc foo def fo  ljk ".replace('foo','yao')
>>>'yao abc yao def fo  ljk '
```

```python
'www.realpython.com'.strip('w.moc')
>>>'realpython'
```

```python
'www.realpython.com'.strip('w.com')
>>>'realpython'
```

```python
'www.realpython.com'.strip('w.ncom')
>>>'realpyth'
```

### **Convert to list** <a href="#convert-to-lists" id="convert-to-lists"></a>

```python
', '.join(['foo','bar','baz','qux'])
>>>'foo, bar, baz, qux'
```

```python
list('corge')
>>>['c', 'o', 'r', 'g', 'e']
```

```python
':'.join('corge')
>>>'c:o:r:g:e'
```

```python
'www.foo'.partition('.')
>>>('www', '.', 'foo')
```

```python
'foo@@bar@@baz'.partition('@@')
>>>('foo', '@@', 'bar@@baz')
```

```python
'foo@@bar@@baz'.rpartition('@@')
>>>('foo@@bar', '@@', 'baz')
```

```python
'foo.bar'.partition('@@')
>>>('foo.bar', '', '')
```

```python

'foo bar adf yao'.rsplit()
>>>['foo', 'bar', 'adf', 'yao']
```

```python
'foo.bar.adf.ert'.split('.')
>>>['foo', 'bar', 'adf', 'ert']
```

```python
'foo\nbar\nadfa\nlko'.splitlines()
>>>['foo', 'bar', 'adfa', 'lko']
```

## 总结 <a href="#zong-jie" id="zong-jie"></a>

除了我以上总结的这些，还有太多非常实用的方法，大家可以根据自己的需求去搜索

* Github仓库地址： [https://github.com/yaozeliang/pandas\_share](https://github.com/yaozeliang/pandas_share/tree/master/Pandas%E4%B9%8B%E6%97%85_04%20pandas%E8%B6%85%E5%AE%9E%E7%94%A8%E6%8A%80%E5%B7%A7)


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