Python Pandas -- DataFrame

Posted 2020-10-30 Jesse_Li

pandas.DataFrame

class pandas.DataFrame(data=None, index=None, columns=None, dtype=None, copy=False)[source]

Two-dimensional size-mutable, potentially heterogeneous tabular data structure with labeled axes (rows and columns). Arithmetic operations align on both row and column labels. Can be thought of as a dict-like container for Series objects. The primary pandas data structure

Parameters:

data : numpy ndarray (structured or homogeneous), dict, or DataFrame Dict can contain Series, arrays, constants, or list-like objects index : Index or array-like Index to use for resulting frame. Will default to np.arange(n) if no indexing information part of input data and no index provided columns : Index or array-like Column labels to use for resulting frame. Will default to np.arange(n) if no column labels are provided dtype : dtype, default None Data type to force. Only a single dtype is allowed. If None, infer copy : boolean, default False Copy data from inputs. Only affects DataFrame / 2d ndarray input

See also

DataFrame.from_records

constructor from tuples, also record arrays

DataFrame.from_dict

from dicts of Series, arrays, or dicts

DataFrame.from_items

from sequence of (key, value) pairs

pandas.read_csv, pandas.read_table, pandas.read_clipboard

1. 先来个小菜

  基于dictionary创建

from pandas import Series, DataFrame
import pandas as pd  
import numpy as np
d = {‘col1‘:[1,2],‘col2‘:[3,4]}
df = pd.DataFrame(data=d)
print(df)
print(df.dtypes)
#   col1  col2
#0     1     3
#1     2     4
#col1    int64
#col2    int64
#dtype: object

基于Numy的ndarrary

df2 = pd.DataFrame(np.random.randint(low=0, high=10, size=(5, 5)),columns=[‘a‘, ‘b‘, ‘c‘, ‘d‘, ‘e‘])
print (df2)
#   a  b  c  d  e
#0  0  2  4  7  0
#1  6  7  3  4  1
#2  5  3  3  8  7
#3  0  9  4  3  4
#4  7  4  7  0  0