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Author: Cola
Source: Coke’s path to data analysis
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Writing in the front
Hello, everyone, I’m Coke.
A Series is a one-dimensional array consisting of a set of data and a set of row indexes. You can think of it as a column of data in Excel without a column name.
To use Series, import the PANDAS module.
import pandas as pd
Copy the code1. To build
Create a new Series, using pd.Series, which can be created from the list
In [1]:S1 = pd.series ([2,4,6,8]) S1 Out[1]:0 2 1 4 2 63 8 dtype:int63Copy the codeThe first column of the output [0,1,2,3] is the index of the sequence S1, and the second column [2,4,6,8] is the value of S1. The most subjective difference from lists is that lists are arranged horizontally, whereas sequences are arranged vertically.
As you can see, the default index increments from 0 without specifying an index. You can also specify an index, as shown in the following example: S2 is given an index incrementing from 1, and assigned with index.
In [2] : S2 = pd Series ([" a ", "b", "d", "e"), the index = [1, 2, 3, 4]) S2 Out [2] : 1 a, 2 b 3 d, 4 e dtype: objectCopy the codeIt can also be created from a dictionary, where the key is the index of the sequence.
In [3]:S3 = pd.Series({"Tom":101,"Tony":102,"Judy":103})
S3
Out[3]:Tom 101
Tony 102
Judy 103
dtype:int64
Copy the code2. To add
Adding data to a sequence actually creates a new sequence and then vertically merges the two sequences. For example, on the basis of S2, S1 is appended to the append method, so as to indirectly realize the addition of data to S2 sequence.
In [4]:S2.append(S1)
Out[4]:1 a
2 b
3 d
4 e
0 2
1 4
2 6
3 8
dtype:object
Copy the codeOr maybe I just want to add an “F” to S2, again.
In [5]:S_f = pd.Series(["f"],index = [5])
S2.append(S_f)
Out[5]:1 a
2 b
3 d
4 e
5 f
dtype:object
Copy the code3. Delete
To drop a, enter the index 1 corresponding to a in the drop column. Note that this is not the default index. It is set to increment from 1.
In [6]:# delete s2. drop([1]) Out[6]:2 b 3 d 4 e 5 f dtype:objectCopy the codeThe above example deletes one value, or you can delete multiple values
Drop ([1,3]) Out[7]:2 b 4 e 5 f dtype:objectCopy the code4. Check
To find out if a value in a sequence also uses the IN operator, I won’t go into that here, but the other method, isin, returns a Boolean value.
Isin ([a,f]) Out[8]:2 FALSE 4 FALSE 5 TRUE DTYPE :boolCopy the codeFind if S2 contains values for “a” and “f”, index 5 is f, so return TRUE, otherwise return FALSE.
To find a value at a specified position in a sequence by accessing an index.
In [9] : # S4 index = pd. The Series ([" c ", "o", "l", "a"], index = [" a ", "2", "three", "four"]) S4 Out [9], "three" lCopy the codeHere we create a new S4 sequence with a custom index [” one “,” two “,” three “,” four “] and find the corresponding value “L” by searching for index “three”.
Slice, access multiple locations, access the top three (including third) data.
In [10]:# slice S4[:3] Out[10]: one c two o three L dType :objectCopy the code5. change
As with any other data structure, it looks up the index and then assigns a value, such as changing C from S4 to D:
In [11]:# modify S4["一"] = "d" S4 Out[11]: d 2 o 3 l 4 a dtype:objectCopy the code