TexStudio doesn't find the package "Pygments" although it is installed

Question

I'm try to use the minted package in latex to display code in latex document. From Texstudio, I get an error message you must have pygmentize installed to use this package .

If I type pip3 install pygments I get Requirement already satisfied: pygments in /usr/local/lib/python3.7/site-packages (2.3.1) which means that pip3 has installed on the machine.

So after typing pip3 show Pygments I get the path where that package is installed namely: /usr/local/lib/python3.7/site-packages. Moreover, when I launch python from the Terminal and type import pygments no error message is displayed. That means that it is correctly installed but that the latex editor cannot find it.

What am I doing wrong?

Edit as pointed in the answers below

I get as the first message:

Package minted Error: You must invoke LaTeX with the -shell-escape flag. \begin

only then I get:

Package minted Error: You must have `pygmentize' installed to use this package. \begin{document}
Package minted Error: Missing Pygments output; \inputminted wasor may be using frozencache with a missing file. \end{minted}^^M
Package minted Error: Missing Pygments output; \inputminted wasor may be using frozencache with a missing file. \end{minted}^^M
Package minted Error: Missing Pygments output; \inputminted wasor may be using frozencache with a missing file. \end{minted}
shell escape is disabled, so I can only detect \ifwindows.

Here is a piece of code:

\documentclass[a4paper, 12pt]{book}
\usepackage{minted}
\begin{document}
\chapter{Introduction}
\begin{minted}{python}
print("hello world")
\end{minted}
\end{document}

Edit 2

As pointed out in another answer, the problem seems to be in the configuration option. So after going in "Textstudio > Preferences > Build" I clicked on the Add button and entered pdflatex -shell-escape in the left cell and pdflatex -synctex=1 -interaction=nonstopmode --shell-escape %.tex in the right cell as shown below:

I do get a new command in the User Menu:

I then quit this menu, but the problem persisted.

What am I still missing

Here is the list of the log file:

Here is the printed log file:

This is pdfTeX, Version 3.14159265-2.6-1.40.19 (TeX Live 2018) (preloaded format=pdflatex 2018.9.16)  23 APR 2019 20:44
entering extended mode
 restricted \write18 enabled.
 %&-line parsing enabled.
**python_latex.tex
(./python_latex.tex
LaTeX2e <2018-04-01> patch level 2
Babel <3.18> and hyphenation patterns for 84 language(s) loaded.
(/usr/local/texlive/2018/texmf-dist/tex/latex/base/book.cls
Document Class: book 2014/09/29 v1.4h Standard LaTeX document class
(/usr/local/texlive/2018/texmf-dist/tex/latex/base/bk12.clo
File: bk12.clo 2014/09/29 v1.4h Standard LaTeX file (size option)
)
\c@part=\count80
\c@chapter=\count81
\c@section=\count82
\c@subsection=\count83
\c@subsubsection=\count84
\c@paragraph=\count85
\c@subparagraph=\count86
\c@figure=\count87
\c@table=\count88
\abovecaptionskip=\skip41
\belowcaptionskip=\skip42
\bibindent=\dimen102
)
(/usr/local/texlive/2018/texmf-dist/tex/latex/minted/minted.sty
Package: minted 2017/07/19 v2.5 Yet another Pygments shim for LaTeX
(/usr/local/texlive/2018/texmf-dist/tex/latex/graphics/keyval.sty
Package: keyval 2014/10/28 v1.15 key=value parser (DPC)
\KV@toks@=\toks14
)
(/usr/local/texlive/2018/texmf-dist/tex/latex/oberdiek/kvoptions.sty
Package: kvoptions 2016/05/16 v3.12 Key value format for package options (HO)
(/usr/local/texlive/2018/texmf-dist/tex/generic/oberdiek/ltxcmds.sty
Package: ltxcmds 2016/05/16 v1.23 LaTeX kernel commands for general use (HO)
)
(/usr/local/texlive/2018/texmf-dist/tex/generic/oberdiek/kvsetkeys.sty
Package: kvsetkeys 2016/05/16 v1.17 Key value parser (HO)
(/usr/local/texlive/2018/texmf-dist/tex/generic/oberdiek/infwarerr.sty
Package: infwarerr 2016/05/16 v1.4 Providing info/warning/error messages (HO)
)
(/usr/local/texlive/2018/texmf-dist/tex/generic/oberdiek/etexcmds.sty
Package: etexcmds 2016/05/16 v1.6 Avoid name clashes with e-TeX commands (HO)
(/usr/local/texlive/2018/texmf-dist/tex/generic/oberdiek/ifluatex.sty
Package: ifluatex 2016/05/16 v1.4 Provides the ifluatex switch (HO)
Package ifluatex Info: LuaTeX not detected.
)
Package etexcmds Info: Could not find \expanded.
(etexcmds)             That can mean that you are not using pdfTeX 1.50 or
(etexcmds)             that some package has redefined \expanded.
(etexcmds)             In the latter case, load this package earlier.
)))
(/usr/local/texlive/2018/texmf-dist/tex/latex/fvextra/fvextra.sty
Package: fvextra 2017/07/08 v1.3.1 fvextra - extensions and patches for fancyvr
b
(/usr/local/texlive/2018/texmf-dist/tex/latex/base/ifthen.sty
Package: ifthen 2014/09/29 v1.1c Standard LaTeX ifthen package (DPC)
)
(/usr/local/texlive/2018/texmf-dist/tex/latex/etoolbox/etoolbox.sty
Package: etoolbox 2018/02/11 v2.5e e-TeX tools for LaTeX (JAW)
\etb@tempcnta=\count89
)
(/usr/local/texlive/2018/texmf-dist/tex/latex/fancyvrb/fancyvrb.sty
Package: fancyvrb 2008/02/07
Style option: `fancyvrb' v2.7a, with DG/SPQR fixes, and firstline=lastline fix 
<2008/02/07> (tvz)
\FV@CodeLineNo=\count90
\FV@InFile=\read1
\FV@TabBox=\box26
\c@FancyVerbLine=\count91
\FV@StepNumber=\count92
\FV@OutFile=\write3
)
(/usr/local/texlive/2018/texmf-dist/tex/latex/upquote/upquote.sty
Package: upquote 2012/04/19 v1.3 upright-quote and grave-accent glyphs in verba
tim
)
(/usr/local/texlive/2018/texmf-dist/tex/latex/lineno/lineno.sty
Package: lineno 2005/11/02 line numbers on paragraphs v4.41
\linenopenalty=\count93
\output=\toks15
\linenoprevgraf=\count94
\linenumbersep=\dimen103
\linenumberwidth=\dimen104
\c@linenumber=\count95
\c@pagewiselinenumber=\count96
\c@LN@truepage=\count97
\c@internallinenumber=\count98
\c@internallinenumbers=\count99
\quotelinenumbersep=\dimen105
\bframerule=\dimen106
\bframesep=\dimen107
\bframebox=\box27
LaTeX Info: Redefining \ on input line 3056.
)
\c@FV@TrueTabGroupLevel=\count100
\c@FV@TrueTabCounter=\count101
\FV@TabBox@Group=\box28
\FV@TmpLength=\skip43
\c@FV@HighlightLinesStart=\count102
\c@FV@HighlightLinesStop=\count103
\FV@LoopCount=\count104
\FV@NCharsBox=\box29
\FV@BreakIndent=\dimen108
\FV@BreakIndentNChars=\count105
\FV@BreakSymbolSepLeft=\dimen109
\FV@BreakSymbolSepLeftNChars=\count106
\FV@BreakSymbolSepRight=\dimen110
\FV@BreakSymbolSepRightNChars=\count107
\FV@BreakSymbolIndentLeft=\dimen111
\FV@BreakSymbolIndentLeftNChars=\count108
\FV@BreakSymbolIndentRight=\dimen112
\FV@BreakSymbolIndentRightNChars=\count109
\c@FancyVerbLineBreakLast=\count110
\FV@LineBox=\box30
\FV@LineIndentBox=\box31
)
(/usr/local/texlive/2018/texmf-dist/tex/latex/tools/calc.sty
Package: calc 2017/05/25 v4.3 Infix arithmetic (KKT,FJ)
\calc@Acount=\count111
\calc@Bcount=\count112
\calc@Adimen=\dimen113
\calc@Bdimen=\dimen114
\calc@Askip=\skip44
\calc@Bskip=\skip45
LaTeX Info: Redefining \setlength on input line 80.
LaTeX Info: Redefining \addtolength on input line 81.
\calc@Ccount=\count113
\calc@Cskip=\skip46
)
(/usr/local/texlive/2018/texmf-dist/tex/latex/tools/shellesc.sty
Package: shellesc 2016/06/07 v0.02a unified shell escape interface for LaTeX
Package shellesc Info: Restricted shell escape enabled on input line 69.
)
(/usr/local/texlive/2018/texmf-dist/tex/latex/ifplatform/ifplatform.sty
Package: ifplatform 2017/10/13 v0.4a Testing for the operating system
(/usr/local/texlive/2018/texmf-dist/tex/generic/oberdiek/pdftexcmds.sty
Package: pdftexcmds 2018/01/30 v0.27 Utility functions of pdfTeX for LuaTeX (HO
)
(/usr/local/texlive/2018/texmf-dist/tex/generic/oberdiek/ifpdf.sty
Package: ifpdf 2017/03/15 v3.2 Provides the ifpdf switch
)
Package pdftexcmds Info: LuaTeX not detected.
Package pdftexcmds Info: \pdf@primitive is available.
Package pdftexcmds Info: \pdf@ifprimitive is available.
Package pdftexcmds Info: \pdfdraftmode found.
)
(/usr/local/texlive/2018/texmf-dist/tex/generic/oberdiek/catchfile.sty
Package: catchfile 2016/05/16 v1.7 Catch the contents of a file (HO)
)
Package ifplatform Warning: 
    shell escape is disabled, so I can only detect \ifwindows.
) (/usr/local/texlive/2018/texmf-dist/tex/generic/xstring/xstring.sty
(/usr/local/texlive/2018/texmf-dist/tex/generic/xstring/xstring.tex
@xs@message=\write4
\integerpart=\count114
\decimalpart=\count115
)
Package: xstring 2013/10/13  v1.7c  String manipulations (C Tellechea)
)
(/usr/local/texlive/2018/texmf-dist/tex/latex/framed/framed.sty
Package: framed 2011/10/22 v 0.96: framed or shaded text with page breaks
\OuterFrameSep=\skip47
\fb@frw=\dimen115
\fb@frh=\dimen116
\FrameRule=\dimen117
\FrameSep=\dimen118
)
(/usr/local/texlive/2018/texmf-dist/tex/latex/float/float.sty
Package: float 2001/11/08 v1.3d Float enhancements (AL)
\c@float@type=\count116
\float@exts=\toks16
\float@box=\box32
@float@everytoks=\toks17
@floatcapt=\box33
)
\minted@appexistsfile=\read2
\minted@bgbox=\box34
\minted@code=\write5
\c@minted@FancyVerbLineTemp=\count117
\c@minted@pygmentizecounter=\count118
@float@every@listing=\toks18
\c@listing=\count119
)
runsystem(mkdir -p _minted-python_latex)...disabled (restricted).
! Package minted Error: You must invoke LaTeX with the -shell-escape flag.
See the minted package documentation for explanation.
Type  H <return>  for immediate help.
 ...
l.3 \begin
          {document}
Pass the -shell-escape flag to LaTeX. Refer to the minted.sty documentation for
 more information.
(/usr/local/texlive/2018/texmf-dist/tex/latex/xcolor/xcolor.sty
Package: xcolor 2016/05/11 v2.12 LaTeX color extensions (UK)
(/usr/local/texlive/2018/texmf-dist/tex/latex/graphics-cfg/color.cfg
File: color.cfg 2016/01/02 v1.6 sample color configuration
)
Package xcolor Info: Driver file: pdftex.def on input line 225.
(/usr/local/texlive/2018/texmf-dist/tex/latex/graphics-def/pdftex.def
File: pdftex.def 2018/01/08 v1.0l Graphics/color driver for pdftex
)
Package xcolor Info: Model cmy' substituted bycmy0' on input line 1348.
Package xcolor Info: Model hsb' substituted byrgb' on input line 1352.
Package xcolor Info: Model RGB' extended on input line 1364. Package xcolor Info: ModelHTML' substituted by rgb' on input line 1366. Package xcolor Info: ModelHsb' substituted by hsb' on input line 1367. Package xcolor Info: ModeltHsb' substituted by hsb' on input line 1368. Package xcolor Info: ModelHSB' substituted by hsb' on input line 1369. Package xcolor Info: ModelGray' substituted by gray' on input line 1370. Package xcolor Info: Modelwave' substituted by `hsb' on input line 1371.
)
runsystem(which pygmentize && touch python_latex.aex)...disabled (restricted).
! Package minted Error: You must have `pygmentize' installed to use this packag
e.
See the minted package documentation for explanation.
Type  H <return>  for immediate help.
 ...
l.3 \begin{document}
Refer to the installation instructions in the minted documentation for more inf
ormation.
(./python_latex.aux)
\openout1 = `python_latex.aux'.
LaTeX Font Info:    Checking defaults for OML/cmm/m/it on input line 3.
LaTeX Font Info:    ... okay on input line 3.
LaTeX Font Info:    Checking defaults for T1/cmr/m/n on input line 3.
LaTeX Font Info:    ... okay on input line 3.
LaTeX Font Info:    Checking defaults for OT1/cmr/m/n on input line 3.
LaTeX Font Info:    ... okay on input line 3.
LaTeX Font Info:    Checking defaults for OMS/cmsy/m/n on input line 3.
LaTeX Font Info:    ... okay on input line 3.
LaTeX Font Info:    Checking defaults for OMX/cmex/m/n on input line 3.
LaTeX Font Info:    ... okay on input line 3.
LaTeX Font Info:    Checking defaults for U/cmr/m/n on input line 3.
LaTeX Font Info:    ... okay on input line 3.
(/usr/local/texlive/2018/texmf-dist/tex/context/base/mkii/supp-pdf.mkii
[Loading MPS to PDF converter (version 2006.09.02).]
\scratchcounter=\count120
\scratchdimen=\dimen119
\scratchbox=\box35
\nofMPsegments=\count121
\nofMParguments=\count122
\everyMPshowfont=\toks19
\MPscratchCnt=\count123
\MPscratchDim=\dimen120
\MPnumerator=\count124
\makeMPintoPDFobject=\count125
\everyMPtoPDFconversion=\toks20
)
Chapter 1.
\openout3 = `python_latex.pyg'.
runsystem(pygmentize -S default -f latex -P commandprefix=PYG > minted-python
latex/default-pyg-prefix.pygstyle)...disabled (restricted).
! Package minted Error: Missing Pygments output; \inputminted was
probably given a file that does not exist--otherwise, you may need 
the outputdir package option, or may be using an incompatible build tool,
or may be using frozencache with a missing file.
See the minted package documentation for explanation.
Type  H <return>  for immediate help.
 ...
l.7 \end{minted}^^M
This could be caused by using -output-directory or -aux-directory 
without setting minted's outputdir, or by using a build tool that 
changes paths in ways minted cannot detect, 
or using frozencache with a missing file.
runsystem(pygmentize -S default -f latex -P commandprefix=PYGdefault > _minted-
python_latex/default.pygstyle)...disabled (restricted).
! Package minted Error: Missing Pygments output; \inputminted was
probably given a file that does not exist--otherwise, you may need 
the outputdir package option, or may be using an incompatible build tool,
or may be using frozencache with a missing file.
See the minted package documentation for explanation.
Type  H <return>  for immediate help.
 ...
l.7 \end{minted}^^M
This could be caused by using -output-directory or -aux-directory 
without setting minted's outputdir, or by using a build tool that 
changes paths in ways minted cannot detect, 
or using frozencache with a missing file.
runsystem(pygmentize -l python -f latex -P commandprefix=PYG -F tokenmerge -o _
minted-python_latex/72214DB4E1E543018D1BAFE86EA3B4440B40C301701A64D52CDA79C72DA
628CC.pygtex python_latex.pyg)...disabled (restricted).
! Package minted Error: Missing Pygments output; \inputminted was
probably given a file that does not exist--otherwise, you may need 
the outputdir package option, or may be using an incompatible build tool,
or may be using frozencache with a missing file.
See the minted package documentation for explanation.
Type  H <return>  for immediate help.
 ...
l.7 \end{minted}
This could be caused by using -output-directory or -aux-directory 
without setting minted's outputdir, or by using a build tool that 
changes paths in ways minted cannot detect, 
or using frozencache with a missing file.
[1
{/usr/local/texlive/2018/texmf-var/fonts/map/pdftex/updmap/pdftex.map}]
(./python_latex.aux)
runsystem(rm python_latex.pyg)...disabled (restricted).
) 
Here is how much of TeX's memory you used:
 4355 strings out of 492649
 78111 string characters out of 6129622
 188991 words of memory out of 5000000
 8209 multiletter control sequences out of 15000+600000
 4544 words of font info for 17 fonts, out of 8000000 for 9000
 1141 hyphenation exceptions out of 8191
 37i,5n,35p,843b,142s stack positions out of 5000i,500n,10000p,200000b,80000s
</usr/local/texlive/2018/texmf-dist/fonts/type1/public/amsfonts/cm/cmbx12.pfb
></usr/local/texlive/2018/texmf-dist/fonts/type1/public/amsfonts/cm/cmr12.pfb>
Output written on python_latex.pdf (1 page, 17712 bytes).
PDF statistics:
 16 PDF objects out of 1000 (max. 8388607)
 10 compressed objects within 1 object stream
 0 named destinations out of 1000 (max. 500000)
 1 words of extra memory for PDF output out of 10000 (max. 10000000)

ANSWER As pointed out in the post from the linked question just insert the following line in the document: % !TeX TXS-program:compile = txs:///pdflatex/[--shell-escape]

Answer 1

is

! Package minted Error: You must have 'pygmentize' installed to use this package.

The first error message you get or before that do you get

! Package minted Error: You must invoke LaTeX with the -shell-escape flag.

Check the log file from the latex run which should also not say on line 3

restricted \write18 enabled.

it should say

\write18 enabled.

If the log is saying restricted write18, then use the -shell-escape option to pdflatex.