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社区首页 >专栏 >Pandas,让Python像R一样处理数据,但快

Pandas,让Python像R一样处理数据,但快

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生信宝典
发布2018-02-05 10:59:58
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发布2018-02-05 10:59:58
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文章被收录于专栏:生信宝典生信宝典

What is pandas

Pandas是python中用于处理矩阵样数据的功能强大的包,提供了R中的dataframevector的操作,使得我们在使用python时,也可以方便、简单、快捷、高效地进行矩阵数据处理。

具体介绍详见http://pandas.pydata.org/。

  • A fast and efficient DataFrame object for data manipulation with integrated indexing;
  • Tools for reading and writing data between in-memory data structures and different formats: CSV and text files, Microsoft Excel, SQL databases, and the fast HDF5 format;
  • Intelligent data alignment and integrated handling of missing data: gain automatic label-based alignment in computations and easily manipulate messy data into an orderly form;
  • Flexible reshaping and pivoting of data sets;
  • Intelligent label-based slicing, fancy indexing, and subsetting of large data sets;
  • Columns can be inserted and deleted from data structures for size mutability;
  • Aggregating or transforming data with a powerful group by engine allowing split-apply-combine operations on data sets;
  • High performance merging and joining of data sets;
  • Hierarchical axis indexing provides an intuitive way of working with high-dimensional data in a lower-dimensional data structure;
  • Time series-functionality: date range generation and frequency conversion, moving window statistics, moving window linear regressions, date shifting and lagging. Even create domain-specific time offsets and join time series without losing data;
  • Highly optimized for performance, with critical code paths written in Cython or C.
  • Python with pandas is in use in a wide variety of academic and commercial domains, including Finance, Neuroscience, Economics, Statistics, Advertising, Web Analytics, and more.
代码语言:javascript
复制
%matplotlib inline

#import plotly
#plotly.offline.init_notebook_mode()

import matplotlib
matplotlib.style.use('ggplot')
import numpy as np
import matplotlib.pyplot as plt
import pandas as pd
import os
from glob import glob

Pandas读取文件

获取目标文件
代码语言:javascript
复制
dir_1 = "pandas_data/"
glob(dir_1+'*')
代码语言:javascript
复制
['pandas_data/ENCFF289HGQ.tsv',
 'pandas_data/gencode.v24.ENS2SYN',
 'pandas_data/ENCFF262OBL.tsv',
 'pandas_data/Gene_metadata_primary_wt_whole_cell.tsv',
 'pandas_data/ENCFF673KYR.tsv',
 'pandas_data/ENCFF060LPA.tsv']
查看目标文件内容和格式

Ipython中可以通过在Linux命令前加!调用系统命令,更多使用见http://ipython.org/ipython-doc/3/interactive/reference.html#system-shell-access.

代码语言:javascript
复制
!head -n 4 pandas_data/gencode.v24.ENS2SYN
代码语言:javascript
复制
gene_id    gene_symbol

ENSG00000223972.5    DDX11L1

ENSG00000227232.5    WASH7P

ENSG00000278267.1    MIR6859-1
代码语言:javascript
复制
!head -n 4 pandas_data/ENCFF556YSD.tsv
代码语言:javascript
复制
transcript_id    gene_id    length    effective_length    expected_count    TPM    FPKM

ENST00000373020.4    ENSG00000000003.10    2206    1925.57    997.23    1.71    7.21

ENST00000494424.1    ENSG00000000003.10    820    539.58    24.77    0.15    0.64

ENST00000496771.1    ENSG00000000003.10    1025    744.57    0.00    0.00    0.00
读取两列文件
代码语言:javascript
复制
ens2syn_file = "pandas_data/gencode.v24.ENS2SYN"
代码语言:javascript
复制
# pandas中的计数都是从0开始的
# header=0: 指定第一行包含列的名字
# index_col=0: 指定第一列为行的名字
ens2syn = pd.read_table(ens2syn_file, header=0, index_col=0)
数据表的索引
  • 数值索引和布尔值索引是按行选取
  • 字符串索引是按列选取
  • 行和列是等效的,应用于行的选取函数也可应用于列,反之亦然
按行选取数据
代码语言:javascript
复制
ens2syn[:3]

gene_symbol

gene_id

ENSG00000223972.5

DDX11L1

ENSG00000227232.5

WASH7P

ENSG00000278267.1

MIR6859-1

取出索引中包含特定值的行
代码语言:javascript
复制
ens2syn[ens2syn.index=="ENSG00000227232.5"]

gene_symbol

gene_id

ENSG00000227232.5

WASH7P

取出某列包含特定值列表的行
代码语言:javascript
复制
ens2syn[ens2syn['gene_symbol'].isin(['DDX11L1','MIR6859-1'])]

gene_symbol

gene_id

ENSG00000223972.5

DDX11L1

ENSG00000278267.1

MIR6859-1

使用正则表达式选取符合要求的行
代码语言:javascript
复制
# head: 只展示部分数据
ens2syn[ens2syn.index.str.contains(r'ENSG0000022')].head()

gene_symbol

gene_id

ENSG00000223972.5

DDX11L1

ENSG00000227232.5

WASH7P

ENSG00000222623.1

RNU6-1100P

ENSG00000228463.9

AP006222.2

ENSG00000224813.3

SEPT14P13

读取多列文件

gzip, bzip压缩的文件也可以直接读取,但是需要保证文件后缀的正确。read_table默认参数可以自动检测文件的格式,根据文件的后缀 ‘.gz’, ‘.bz2’, ‘.zip’, or ‘xz’分别使用 gzip, bz2, zip or xz读取。

代码语言:javascript
复制
tsvL = glob(dir_1+'ENC*.tsv')
tsvL
代码语言:javascript
复制
['pandas_data/ENCFF289HGQ.tsv',
 'pandas_data/ENCFF262OBL.tsv',
 'pandas_data/ENCFF673KYR.tsv',
 'pandas_data/ENCFF060LPA.tsv']
代码语言:javascript
复制
index = 0
tsvFile = tsvL[index]
expr = pd.read_table(tsvFile, header=0, index_col=0)
expr.head(3)

transcript_id(s)

length

effective_length

expected_count

TPM

FPKM

gene_id

ENSG00000000003.14

ENST00000373020.8,ENST00000494424.1,ENST000004…

2198.69

1939.24

2827.0

1.03

10.84

ENSG00000000005.5

ENST00000373031.4,ENST00000485971.1

940.50

681.07

0.0

0.00

0.00

ENSG00000000419.12

ENST00000371582.8,ENST00000371584.8,ENST000003…

1079.84

820.38

1680.0

1.45

15.23

选取多列数据

列的输出顺序与给定的列名字的顺序一致

代码语言:javascript
复制
expr[['FPKM','TPM']].head(3)

FPKM

TPM

gene_id

ENSG00000000003.14

10.84

1.03

ENSG00000000005.5

0.00

0.00

ENSG00000000419.12

15.23

1.45

重命名列名字

从Dataframe中只选取一列时,数据框会被转换成Series,因此需要使用pd.loc[:,[column_name]](虽然内部的方括号内只有一个值,但写法是必须的)索引。

代码语言:javascript
复制
# 因为要把多个文件的同一类型表达值合并到一个文件,我们使用文件名作为列的名字
name = os.path.split(tsvFile)[-1][:-4]
print name
expr_tpm = expr.loc[:,['TPM']] # 取出所有的行和名字为TPM的列
expr_tpm.columns=[name]  
expr_tpm[:3]
代码语言:javascript
复制
ENCFF289HGQ

ENCFF289HGQ

gene_id

ENSG00000000003.14

1.03

ENSG00000000005.5

0.00

ENSG00000000419.12

1.45

合并矩阵
定义函数简化文件读取
代码语言:javascript
复制
# 为了读取多个文件,定义一个函数简化操作
def readExpr_1(tsvFileL, typeL=['TPM','FPKM']):
    '''
    tsvFileL: lists of files waiting for reading
    resultD: a dictionary to save data matrix
            {'TPM':[mat1, mat2,...]
             'FPKM':[mat1, mat2, ...]}
    typeL; list of names for columns to be extracted
    '''
    resultD = {}
    for _type in typeL: resultD[_type] = []

    for tsvFile in tsvFileL:
        expr = pd.read_table(tsvFile, header=0, index_col=0)
        name = os.path.split(tsvFile)[-1][:-4]  #this options is very arbitary
        for _type in typeL: # add _ to type to avoid override Python inner function `type` 
            expr_type = expr.loc[:,[_type]]
            expr_type.columns = [name]
            resultD[_type].append(expr_type)
    return resultD
#-----------------------------------------------------
代码语言:javascript
复制
exprD = readExpr_1(tsvL)
TPM_mat = exprD['TPM']
FPKM_mat = exprD['FPKM']
使用pd.merge合并矩阵示例

先从刚才读取的矩阵中选出2个测试下pandas中的矩阵合并方法和效果

代码语言:javascript
复制
# 选取第一个矩阵
_idL = ['ENSG00000000003.14', 'ENSG00000000005.5','ENSG00000000419.12','ENSG00000000457.13']
mat1 = TPM_mat[0]
mat1 = mat1[mat1.index.isin(_idL)]
mat1

ENCFF289HGQ

gene_id

ENSG00000000003.14

1.03

ENSG00000000005.5

0.00

ENSG00000000419.12

1.45

ENSG00000000457.13

0.24

代码语言:javascript
复制
# 选取第二个矩阵
_idL = ['ENSG00000001561.6','ENSG00000000003.14', 'ENSG00000000419.12','ENSG00000001036.13']
mat2 = TPM_mat[1]
mat2 = mat2[mat2.index.isin(_idL)]
mat2

ENCFF262OBL

gene_id

ENSG00000000003.14

17.13

ENSG00000000419.12

18.86

ENSG00000001036.13

10.34

ENSG00000001561.6

2.47

基于索引(index)的合并

代码语言:javascript
复制
* outer: 合并所有的索引,缺失值填充NA
* inner:保留共有的索引
* left:使用第一个矩阵的索引
* right:使用第二个矩阵的索引
代码语言:javascript
复制
pd.merge(mat1, mat2, left_index=True, right_index=True, how="outer")

ENCFF289HGQ

ENCFF262OBL

gene_id

ENSG00000000003.14

1.03

17.13

ENSG00000000005.5

0.00

NaN

ENSG00000000419.12

1.45

18.86

ENSG00000000457.13

0.24

NaN

ENSG00000001036.13

NaN

10.34

ENSG00000001561.6

NaN

2.47

代码语言:javascript
复制
pd.merge(mat1, mat2, left_index=True, right_index=True, how="inner")

ENCFF289HGQ

ENCFF262OBL

gene_id

ENSG00000000003.14

1.03

17.13

ENSG00000000419.12

1.45

18.86

代码语言:javascript
复制
pd.merge(mat1, mat2, left_index=True, right_index=True, how="left")

ENCFF289HGQ

ENCFF262OBL

gene_id

ENSG00000000003.14

1.03

17.13

ENSG00000000005.5

0.00

NaN

ENSG00000000419.12

1.45

18.86

ENSG00000000457.13

0.24

NaN

使用pd.concat合并矩阵示例

对于较多的数据表合并操作时,concatmerge要简单快速很多。

代码语言:javascript
复制
pd.concat([mat1, mat2], axis=1)

ENCFF289HGQ

ENCFF262OBL

ENSG00000000003.14

1.03

17.13

ENSG00000000005.5

0.00

NaN

ENSG00000000419.12

1.45

18.86

ENSG00000000457.13

0.24

NaN

ENSG00000001036.13

NaN

10.34

ENSG00000001561.6

NaN

2.47

代码语言:javascript
复制
pd.concat([mat1, mat2], axis=1, join="inner")

ENCFF289HGQ

ENCFF262OBL

gene_id

ENSG00000000003.14

1.03

17.13

ENSG00000000419.12

1.45

18.86

使用pd.join合并矩阵示例
代码语言:javascript
复制
mat3 = mat1.join(mat2, how="outer")
mat3

ENCFF289HGQ

ENCFF262OBL

gene_id

ENSG00000000003.14

1.03

17.13

ENSG00000000005.5

0.00

NaN

ENSG00000000419.12

1.45

18.86

ENSG00000000457.13

0.24

NaN

ENSG00000001036.13

NaN

10.34

ENSG00000001561.6

NaN

2.47

替换NA值为0

代码语言:javascript
复制
mat3 = mat3.fillna(0)
mat3

ENCFF289HGQ

ENCFF262OBL

gene_id

ENSG00000000003.14

1.03

17.13

ENSG00000000005.5

0.00

0.00

ENSG00000000419.12

1.45

18.86

ENSG00000000457.13

0.24

0.00

ENSG00000001036.13

0.00

10.34

ENSG00000001561.6

0.00

2.47

去除所有值都为0的行

代码语言:javascript
复制
#Both works well here
#mat3[(mat3>0).any(axis=1)]
mat3.loc[(mat3>0).any(axis=1)]

ENCFF289HGQ

ENCFF262OBL

gene_id

ENSG00000000003.14

1.03

17.13

ENSG00000000419.12

1.45

18.86

ENSG00000000457.13

0.24

0.00

ENSG00000001036.13

0.00

10.34

ENSG00000001561.6

0.00

2.47

测试三种方法使用的内存和速度比较

速度:concat>join>>merge

内存:相当

代码语言:javascript
复制
%timeit test_merge = reduce(lambda left,right: pd.merge(left,right,left_index=True,right_index=True,how='outer'), TPM_mat)
代码语言:javascript
复制
100 loops, best of 3: 3.36 ms per loop
代码语言:javascript
复制
%timeit test_merge = pd.concat(TPM_mat, axis=1)
代码语言:javascript
复制
1000 loops, best of 3: 1.21 ms per loop
代码语言:javascript
复制
%timeit TPM_mat[0].join(TPM_mat[1:], how="outer")
代码语言:javascript
复制
1000 loops, best of 3: 1.25 ms per loop
代码语言:javascript
复制
%load_ext memory_profiler
代码语言:javascript
复制
%memit test_merge = reduce(lambda left,right: pd.merge(left,right,left_index=True,right_index=True,how='outer'), TPM_mat)
代码语言:javascript
复制
peak memory: 107.32 MiB, increment: 0.01 MiB
代码语言:javascript
复制
%memit test_merge = pd.concat(TPM_mat, axis=1)
代码语言:javascript
复制
peak memory: 107.30 MiB, increment: 0.10 MiB
代码语言:javascript
复制
%memit TPM_mat[0].join(TPM_mat[1:], how="outer")
代码语言:javascript
复制
peak memory: 107.32 MiB, increment: 0.00 MiB
重写函数完成文件的读写和矩阵的合并
代码语言:javascript
复制
# 读取多个文件,并且合并矩阵,定义一个函数简化操作
def concatExpr(tsvFileL, typeL=['TPM','FPKM']):
    '''
    tsvFileL: lists of files waiting for reading
    resultD: a dictionary to save data matrix
            {'TPM':[mat1, mat2,...]
             'FPKM':[mat1, mat2, ...]}
    typeL; list of names for columns to be extracted
    '''
    resultD = {}
    for _type in typeL: resultD[_type] = []

    for tsvFile in tsvFileL:
        expr = pd.read_table(tsvFile, header=0, index_col=0)
        name = os.path.split(tsvFile)[-1][:-4]  #this options is very arbitary
        for _type in typeL: # add _ to type to avoid override Python inner function `type` 
            expr_type = expr.loc[:,[_type]]
            expr_type.columns = [name]
            resultD[_type].append(expr_type)
    #-------------------------------------------
    mergeD = {}
    for _type in typeL:
        mergeM = pd.concat(resultD[_type], axis=1)
        mergeM = mergeM.fillna(0) # Substitute all NA with 0
        mergeM = mergeM.loc[(mergeM>0).any(axis=1)] # Delete aoo zero rows.
        mergeD[_type] = mergeM
    return mergeD
#-----------------------------------------------------
代码语言:javascript
复制
typeL = ['TPM','FPKM']
exprD = concatExpr(tsvL, typeL)
TPM_mat = exprD['TPM']
FPKM_mat = exprD['FPKM']
代码语言:javascript
复制
TPM_mat.head()

ENCFF289HGQ

ENCFF262OBL

ENCFF673KYR

ENCFF060LPA

gene_id

ENSG00000000003.14

1.03

17.13

2.42

6.64

ENSG00000000419.12

1.45

18.86

1.80

9.91

ENSG00000000457.13

0.24

2.48

0.38

0.86

ENSG00000000460.16

0.26

5.36

0.16

1.51

ENSG00000000938.12

0.00

0.05

0.00

0.01

矩阵数据提取

只保留表达矩阵中存储的基因的IDSymbol对照表

代码语言:javascript
复制
# 回顾下数据格式
ens2syn.head(3)

gene_symbol

gene_id

ENSG00000223972.5

DDX11L1

ENSG00000227232.5

WASH7P

ENSG00000278267.1

MIR6859-1

代码语言:javascript
复制
ens2syn.shape
代码语言:javascript
复制
(60725, 1)
代码语言:javascript
复制
ens2syn = ens2syn[ens2syn.index.isin(TPM_mat.index)]
代码语言:javascript
复制
ens2syn.shape
代码语言:javascript
复制
(48, 1)
代码语言:javascript
复制
ens2syn.head(3)

gene_symbol

gene_id

ENSG00000001460.17

STPG1

ENSG00000001461.16

NIPAL3

ENSG00000000938.12

FGR

读取META data文件
代码语言:javascript
复制
meta = "pandas_data/meta.tsv"
metaM = pd.read_table(meta, header=0, index_col=0)
# 重名了列的名字
oriColnames = metaM.columns.values
nameD = dict([(i,i.replace(' ','_')) for i in oriColnames])
metaM.rename(columns=nameD, inplace=True)
metaM.head(3)

File format

Output type

Experiment accession

Assay

Biosample term id

Biosample term name

Biosample type

Biosample life stage

Biosample sex

Biosample organism

md5sum

File download URL

Assembly

Platform

Controlled by

File Status

Audit WARNING

Audit INTERNAL_ACTION

Audit NOT_COMPLIANT

Audit ERROR

File accession

ENCFF120PLK

tsv

gene quantifications

ENCSR198TKA

RNA-seq

CL:0000650

mesangial cell

primary cell

unknown, fetal

unknown, female

Homo sapiens

1e9a3db25f5361b2ca454d1df427f430

https://www.encodeproject.org/files/ENCFF120PL…

hg19

NaN

NaN

released

NaN

NaN

NaN

NaN

ENCFF805BVE

tsv

gene quantifications

ENCSR198TKA

RNA-seq

CL:0000650

mesangial cell

primary cell

unknown, fetal

unknown, female

Homo sapiens

ee0e94d6795ed7c2ef69c61b1d29eb02

https://www.encodeproject.org/files/ENCFF805BV…

hg19

NaN

NaN

released

NaN

NaN

NaN

NaN

ENCFF850RHD

tsv

gene quantifications

ENCSR198TKA

RNA-seq

CL:0000650

mesangial cell

primary cell

unknown, fetal

unknown, female

Homo sapiens

22f948135c0935516f19f6b995ccc30c

https://www.encodeproject.org/files/ENCFF850RH…

GRCh38

NaN

NaN

released

NaN

NaN

NaN

NaN

3 rows × 47 columns

只保留前面提到的4个样品的数据
代码语言:javascript
复制
sampleL = TPM_mat.columns.values
metaM = metaM[metaM.index.isin(sampleL)]
# 同时索引行和列
metaM.ix[:4,:5]

Biosample term id

Biosample term name

Biosample type

Biosample life stage

Biosample sex

File accession

ENCFF673KYR

CL:0000650

mesangial cell

primary cell

unknown, fetal

unknown, female

ENCFF262OBL

CL:1001568

pulmonary artery endothelial cell

primary cell

adult

male

ENCFF060LPA

CL:1001568

pulmonary artery endothelial cell

primary cell

adult

male

ENCFF289HGQ

CL:0002558

fibroblast of villous mesenchyme

primary cell

newborn

male, female

提取目标列信息
代码语言:javascript
复制
# 假如只提取`Biosample`开头的列
#meta_colL = ['Biosample term id', 'Biosample term name']

# Extract columns matching specific patterns
# Both works well, filter is more simple
#metaM.loc[:,metaM.columns.str.contains(r'^Biosample')]
metaM = metaM.filter(regex=("^Biosample"))
metaM

Biosample term id

Biosample term name

Biosample type

Biosample life stage

Biosample sex

Biosample organism

Biosample treatments

Biosample subcellular fraction term name

Biosample phase

Biosample synchronization stage

Biosample Age

File accession

ENCFF673KYR

CL:0000650

mesangial cell

primary cell

unknown, fetal

unknown, female

Homo sapiens

NaN

NaN

NaN

NaN

NaN

ENCFF262OBL

CL:1001568

pulmonary artery endothelial cell

primary cell

adult

male

Homo sapiens

NaN

NaN

NaN

NaN

52 year

ENCFF060LPA

CL:1001568

pulmonary artery endothelial cell

primary cell

adult

male

Homo sapiens

NaN

NaN

NaN

NaN

23 year

ENCFF289HGQ

CL:0002558

fibroblast of villous mesenchyme

primary cell

newborn

male, female

Homo sapiens

NaN

NaN

NaN

NaN

NaN

代码语言:javascript
复制
metaM.fillna('')

Biosample term id

Biosample term name

Biosample type

Biosample life stage

Biosample sex

Biosample organism

Biosample treatments

Biosample subcellular fraction term name

Biosample phase

Biosample synchronization stage

Biosample Age

File accession

ENCFF673KYR

CL:0000650

mesangial cell

primary cell

unknown, fetal

unknown, female

Homo sapiens

ENCFF262OBL

CL:1001568

pulmonary artery endothelial cell

primary cell

adult

male

Homo sapiens

52 year

ENCFF060LPA

CL:1001568

pulmonary artery endothelial cell

primary cell

adult

male

Homo sapiens

23 year

ENCFF289HGQ

CL:0002558

fibroblast of villous mesenchyme

primary cell

newborn

male, female

Homo sapiens

Pandas写入文件

写入文本文件
代码语言:javascript
复制
metaM.to_csv("pandas_data/meta2.tsv", sep="\t")
代码语言:javascript
复制
ens2syn.to_csv("pandas_data/gencode.v24.ENS2SYN", sep="\t")
代码语言:javascript
复制
TPM_mat.to_csv("pandas_data/TPM", sep=b'\t', float_format="%.2f")
写入HDF5文件

HDF5 is a data model, library, and file format for storing and managing data. It supports an unlimited variety of datatypes, and is designed for flexible and efficient I/O and for high volume and complex data. HDF5 is portable and is extensible, allowing applications to evolve in their use of HDF5. The HDF5 Technology suite includes tools and applications for managing, manipulating, viewing, and analyzing data in the HDF5 format. https://support.hdfgroup.org/HDF5/

使用优势是把处理好的数据以二进制文件存取,既可以减少文件数目、压缩使用空间,又可以方便多次快速读取,并且可以在不同的程序语言如Python与R中共同使用。

HDF5文件的写入形式上类似于字典操作,其读取也是。

代码语言:javascript
复制
# 写入模式打开一个HDF5文件,使用压缩格式以节省空间
store = pd.HDFStore("pandas_data/ENCODE.hdf5", "w", complib=str("zlib"), complevel=9)

# 写入表达矩阵
store["TPM"] = TPM_mat
store["FPKM"] = FPKM_mat

# 写入注释文件
store['ens2syn'] = ens2syn
store['meta'] = metaM

# 关闭HDF5句柄
store.close()
代码语言:javascript
复制
/MPATHB/soft/anacond/lib/python2.7/site-packages/IPython/core/interactiveshell.py:3035: PerformanceWarning: 
your performance may suffer as PyTables will pickle object types that it cannot
map directly to c-types [inferred_type->mixed,key->block0_values] [items->['Biosample term id', 'Biosample term name', 'Biosample type', 'Biosample life stage', 'Biosample sex', 'Biosample organism', 'Biosample Age']]

  exec(code_obj, self.user_global_ns, self.user_ns)

当数据中存在混合数据模式时,会出现上面的Warning,对于我们的数据只要把metaM中的NaN值替换掉就可以。

代码语言:javascript
复制
# 写入模式打开一个HDF5文件,使用压缩格式已节省空间
store = pd.HDFStore("pandas_data/ENCODE.hdf5", "w", complib=str("zlib"), complevel=9)

# 写入表达矩阵
store["TPM"] = TPM_mat
store["FPKM"] = FPKM_mat

# 写入注释文件
store['ens2syn'] = ens2syn
store['meta'] = metaM.fillna('')

# 关闭HDF5句柄
store.close()
读取HDF5文件
代码语言:javascript
复制
store = pd.HDFStore("pandas_data/ENCODE.hdf5")
代码语言:javascript
复制
# 列出HDF5文件的索引名字
store.keys()
代码语言:javascript
复制
['/FPKM', '/TPM', '/ens2syn', '/meta']
代码语言:javascript
复制
TPM_mat = store['TPM']
TPM_mat.head(3)

ENCFF289HGQ

ENCFF262OBL

ENCFF673KYR

ENCFF060LPA

gene_id

ENSG00000000003.14

1.03

17.13

2.42

6.64

ENSG00000000419.12

1.45

18.86

1.80

9.91

ENSG00000000457.13

0.24

2.48

0.38

0.86

代码语言:javascript
复制
ens2syn = store['ens2syn']
meta = store['meta']
代码语言:javascript
复制
store.close()

PANDAS矩阵的小应用

利用上面的矩阵操作,选取这两个基因相关的信息并绘制表达谱

代码语言:javascript
复制
targetL = ['KRIT1','AK2']

Gene_symbol转换为Gene_id

代码语言:javascript
复制
ensID = ens2syn[ens2syn["gene_symbol"].isin(targetL)]
ensID

gene_symbol

gene_id

ENSG00000004455.16

AK2

ENSG00000001631.14

KRIT1

提取目标基因的表达

代码语言:javascript
复制
targetExpr = TPM_mat[TPM_mat.index.isin(ensID.index)]
targetExpr

ENCFF289HGQ

ENCFF262OBL

ENCFF673KYR

ENCFF060LPA

gene_id

ENSG00000001631.14

1.15

13.36

1.37

6.21

ENSG00000004455.16

2.31

37.62

8.95

15.57

重命名矩阵的索引

代码语言:javascript
复制
ensID_dict = ensID.to_dict()
ensID_dict
代码语言:javascript
复制
{'gene_symbol': {'ENSG00000001631.14': 'KRIT1', 'ENSG00000004455.16': 'AK2'}}
代码语言:javascript
复制
targetExpr = targetExpr.rename(index=ensID_dict['gene_symbol'])
targetExpr

ENCFF289HGQ

ENCFF262OBL

ENCFF673KYR

ENCFF060LPA

gene_id

KRIT1

1.15

13.36

1.37

6.21

AK2

2.31

37.62

8.95

15.57

转置矩阵以增加META信息

代码语言:javascript
复制
targetExpr_t = targetExpr.T
targetExpr_t

gene_id

KRIT1

AK2

ENCFF289HGQ

1.15

2.31

ENCFF262OBL

13.36

37.62

ENCFF673KYR

1.37

8.95

ENCFF060LPA

6.21

15.57

从meta矩阵中提取4列信息

代码语言:javascript
复制
meta_type = ["Biosample term name","Biosample type", "Biosample life stage", "Biosample sex"]
代码语言:javascript
复制
meta = meta[meta_type]
meta

Biosample term name

Biosample type

Biosample life stage

Biosample sex

File accession

ENCFF673KYR

mesangial cell

primary cell

unknown, fetal

unknown, female

ENCFF262OBL

pulmonary artery endothelial cell

primary cell

adult

male

ENCFF060LPA

pulmonary artery endothelial cell

primary cell

adult

male

ENCFF289HGQ

fibroblast of villous mesenchyme

primary cell

newborn

male, female

修改下矩阵信息,去除unknow,字符串(只是为了展示方便)

代码语言:javascript
复制
meta.loc['ENCFF673KYR',"Biosample life stage"] = "fetal"
# Much faster
meta = meta.set_value('ENCFF673KYR','Biosample sex','female')
meta = meta.set_value('ENCFF289HGQ','Biosample sex','female')
meta

Biosample term name

Biosample type

Biosample life stage

Biosample sex

File accession

ENCFF673KYR

mesangial cell

primary cell

fetal

female

ENCFF262OBL

pulmonary artery endothelial cell

primary cell

adult

male

ENCFF060LPA

pulmonary artery endothelial cell

primary cell

adult

male

ENCFF289HGQ

fibroblast of villous mesenchyme

primary cell

newborn

female

代码语言:javascript
复制
target_expr_meta = targetExpr_t.join(meta, how="left")
target_expr_meta

gene_id

KRIT1

AK2

Biosample term name

Biosample type

Biosample life stage

Biosample sex

ENCFF289HGQ

1.15

2.31

fibroblast of villous mesenchyme

primary cell

newborn

female

ENCFF262OBL

13.36

37.62

pulmonary artery endothelial cell

primary cell

adult

male

ENCFF673KYR

1.37

8.95

mesangial cell

primary cell

fetal

female

ENCFF060LPA

6.21

15.57

pulmonary artery endothelial cell

primary cell

adult

male

重名了列名字(替换掉名字中的空格)

代码语言:javascript
复制
oriColnames = target_expr_meta.columns.values
nameD = dict([(i,i.replace(' ','_')) for i in oriColnames])
target_expr_meta.rename(columns=nameD, inplace=True)
target_expr_meta

gene_id

KRIT1

AK2

Biosample_term_name

Biosample_type

Biosample_life_stage

Biosample_sex

ENCFF289HGQ

1.15

2.31

fibroblast of villous mesenchyme

primary cell

newborn

female

ENCFF262OBL

13.36

37.62

pulmonary artery endothelial cell

primary cell

adult

male

ENCFF673KYR

1.37

8.95

mesangial cell

primary cell

fetal

female

ENCFF060LPA

6.21

15.57

pulmonary artery endothelial cell

primary cell

adult

male

绘制散点图

代码语言:javascript
复制
target_expr_meta.plot.scatter(x='KRIT1', y='AK2')
代码语言:javascript
复制
<matplotlib.axes._subplots.AxesSubplot at 0x7fbcaefc0c10>
代码语言:javascript
复制
/MPATHB/soft/anacond/lib/python2.7/site-packages/matplotlib/collections.py:590: FutureWarning:

elementwise comparison failed; returning scalar instead, but in the future will perform elementwise comparison

绘制箱线图

代码语言:javascript
复制
a = target_expr_meta.boxplot(["KRIT1", "AK2"])
代码语言:javascript
复制
/MPATHB/soft/anacond/lib/python2.7/site-packages/IPython/kernel/__main__.py:1: FutureWarning:

The default value for 'return_type' will change to 'axes' in a future release.
 To use the future behavior now, set return_type='axes'.
 To keep the previous behavior and silence this warning, set return_type='dict'.

使用Plotly绘制交互图

代码语言:javascript
复制
fig = {
    'data': [
        {
            'x': target_expr_meta.KRIT1,
            'y': target_expr_meta.AK2,
            'text': target_expr_meta.Biosample_term_name,
            'mode': 'markers+texts',
            'name': 'Legend name',
            'marker': {
                'symbol':"circle",
                "opacity": "0.9"
            }
        },
        {
            'x': [0,40],
            'y': [0,40],
            'text': "Diagonal",
            'mode': 'lines',
            'name': 'Diagonal line',
            'showlegend': False,
            'line': {
                'color': ('rgb(192,192,192)')
            }
        }
    ],
    'layout': {
        'xaxis': {'title':'KRIT1 expression value','range':[0,40]},
        'yaxis': {'title':'AK2 expression value','range':[0,40]},
        'height':500,
        'width':600,
        'showlegend': True,
         "legend": {
            "x": 0.6,
            "y": 1
        }
    }
}
plotly.offline.iplot(fig)

python fig = { 'data': [ { 'x': target_expr_meta[target_expr_meta['Biosample_sex']==atype].KRIT1, 'y': target_expr_meta[target_expr_meta['Biosample_sex']==atype].AK2, 'text': target_expr_meta[target_expr_meta['Biosample_sex']==atype].Biosample_term_name, 'mode': 'markers+texts', 'name': _type, 'marker': { 'symbol':"circle", "opacity": "0.9" } } for atype in ['female','male'] ], 'layout': { 'xaxis': {'title':'KRIT1 expression value','range':[0,40]}, 'yaxis': {'title':'AK2 expression value','range':[0,40]}, 'height':500, 'width':600, 'showlegend': True, "legend": { "x": 0.6, "y": 1 } } } plotly.offline.iplot(fig)### 使用R读取HDF5文件r #R code for reading hdf5 > h5ls('test.hdf5') group name otype dclass dim 0 / FPKM H5I_GROUP 1 /FPKM axis0 H5I_DATASET STRING 3 2 /FPKM axis1 H5I_DATASET STRING 25135 3 /FPKM block0_items H5I_DATASET STRING 3 4 /FPKM block0_values H5I_DATASET FLOAT x 25135 5 / TPM H5I_GROUP 6 /TPM axis0 H5I_DATASET STRING 3 7 /TPM axis1 H5I_DATASET STRING 24025 8 /TPM block0_items H5I_DATASET STRING 3 9 /TPM block0_values H5I_DATASET FLOAT x 24025 10 / ens2syn H5I_GROUP 11 /ens2syn axis0 H5I_DATASET STRING 1 12 /ens2syn axis1 H5I_DATASET STRING 60725 13 /ens2syn block0_items H5I_DATASET STRING 1 14 /ens2syn block0_values H5I_DATASET VLEN 1 15 / meta H5I_GROUP 16 /meta axis0 H5I_DATASET STRING 47 17 /meta axis1 H5I_DATASET STRING 3 18 /meta block0_items H5I_DATASET STRING 19 19 /meta block0_values H5I_DATASET FLOAT x 3 20 /meta block1_items H5I_DATASET STRING 2 21 /meta block1_values H5I_DATASET INTEGER x 3 22 /meta block2_items H5I_DATASET STRING 26 23 /meta block2_values H5I_DATASET VLEN 1 > TPM = h5read("test.hdf5", "/TPM") > str(TPM) List of 4 $ axis0 : chr [1:3(1d)] "ENCFF673KYR" "ENCFF805ZGF" "ENCFF581ZEU" $ axis1 : chr [1:24025(1d)] "ENSG00000000003.14" "ENSG00000000005.5" "ENSG00000000419.12" "ENSG00000000457.13" ... $ block0_items : chr [1:3(1d)] "ENCFF673KYR" "ENCFF805ZGF" "ENCFF581ZEU" $ block0_values: num [1:3, 1:24025] 2.42 1.64 5.69 0 0 0.11 1.8 3.82 6.38 0.38 ... > d <- TPM$block0_values > rownames(d) <- TPM$axis1 Error in `rownames<-`(`*tmp*`, value = c("ENSG00000000003.14", "ENSG00000000005.5", : length of 'dimnames' [1] not equal to array extent > d <- as.data.frame(TPM$block0_values) > rownames(d) <- TPM$axis1 Error in `row.names<-.data.frame`(`*tmp*`, value = value) : invalid 'row.names' length > dims(d) Error: could not find function "dims" > dim(d) [1] 3 24025 > d <- t(as.data.frame(TPM$block0_values)) > dim(d) [1] 24025 3 > rownames(d) <- TPM$axis1 > colnames(d) <- TPM$axis0 > hed(d) Error: could not find function "hed" > head(d) ENCFF673KYR ENCFF805ZGF ENCFF581ZEU ENSG00000000003.14 2.42 1.64 5.69 ENSG00000000005.5 0.00 0.00 0.11 ENSG00000000419.12 1.80 3.82 6.38 ENSG00000000457.13 0.38 0.57 1.17 ENSG00000000460.16 0.16 0.31 0.14 ENSG00000000938.12 0.00 0.03 0.00### Pandas矩阵生成python np.random.seed(1) df = pd.DataFrame({"first": np.random.rand(100), "second": np.random.rand(100), "class": np.random.randint(0, 2, (100,))}, index=range(100)) df.head()

class

first

second

0

0

0.417022

0.326645

1

0

0.720324

0.527058

2

1

0.000114

0.885942

3

1

0.302333

0.357270

4

1

0.146756

0.908535

Ipython notebook link

https://github.com/Tong-Chen/notebook/blob/master/pandas.ipynb

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目录
  • What is pandas
  • Pandas读取文件
    • 获取目标文件
      • 查看目标文件内容和格式
        • 读取两列文件
          • 数据表的索引
            • 按行选取数据
            • 取出索引中包含特定值的行
            • 取出某列包含特定值列表的行
            • 使用正则表达式选取符合要求的行
          • 读取多列文件
            • 选取多列数据
              • 重命名列名字
                • 合并矩阵
                  • 定义函数简化文件读取
                  • 使用pd.merge合并矩阵示例
                  • 使用pd.concat合并矩阵示例
                  • 使用pd.join合并矩阵示例
                  • 测试三种方法使用的内存和速度比较
                  • 重写函数完成文件的读写和矩阵的合并
                • 矩阵数据提取
                  • 读取META data文件
                    • 只保留前面提到的4个样品的数据
                    • 提取目标列信息
                • Pandas写入文件
                  • 写入文本文件
                    • 写入HDF5文件
                      • 读取HDF5文件
                      • PANDAS矩阵的小应用
                      • Ipython notebook link
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